Chicken Spaghetti Squash Casserole

This yummy low carb and keto Chicken Spaghetti Squash Casserole is brought to you by Fiesta Brand Seasonings!

If you are a fan of traditional Texas dishes like King Ranch Chicken or Chicken Spaghetti…you are in for a treat!  Chicken Spaghetti Squash Casserole combines the comforting flavors of these two dishes into one incredibly delicious low carb, keto friendly, gluten free meal!  All the savory Tex-Mex flavor you love with the classic, creamy, cheesy goodness with no pasta or tortillas!  But how does it taste???  Ya’ll it’s out of this world amazing!

Chicken Spaghetti Casserole plated.

When I want something comforting and easy and casserole is on the menu!  Chicken Spaghetti and King Ranch Chicken are two of my all-time favorite comfort food casserole type dishes!  In fact, they are two family favorites I would always see as a child at family gatherings…my moms’ specialties!  I remember my mom making literally a vat of chicken spaghetti for big family gatherings…to die for!  These are probably two of our most requested family recipes…why?  Because they’re decadent, comforting and so delish!  But healthy?   Not so much! 

I make this traditional King Ranch Chicken for our ranch guests quite often but I was in need of a keto friendly, low carb version for the fam.  The Cowboy is leaning more towards low carb eating these days and King Ranch Chicken is one of his favorites!  The two dishes are pretty similar in flavor so I was pretty sure I could pull of a keto version that was just as good as the originals!

Chicken Spaghetti Casserole ready for the oven!
Chicken Spaghetti Casserole ready for the oven!

So this is my low carb, keto friendly nod to the classic Chicken Spaghetti!

How to Prepare Spaghetti Squash

It all starts with spaghetti squash!  This guy can be a little intimidating but have no fear!  We love using spaghetti squash as a pasta alternative and they are really easy to prepare.  The squash is really hard and can be quite literally a danger to cut through so I like to soften mine up a bit in the microwave before I cut it.  Through it in for 4-5 minutes….let it cool a but and you’re good to go!

Cut both ends off the squash and cut it in half.  It doesn’t really matter the direction you cut it but if you like longer “noodles” cut it through the middle horizontally and or if you don’t mind shorter strands cut it through the center lengthwise.  Scoop out the seeds with a spoon….drizzle with olive oil and a little salt and place the on a lined sheet pan cut side down and roast…that it!  After the initial cutting, easy peasy.

While the squash is roasting you can work on the ingredients for the sauce! 

Pro tip:  I always keep shredded chicken in the freezer.  Whenever I roast chicken for dinner, I always cook one extra, shred it up and store it in the freezer to use in a quick weeknight meal!

The base for this low carb Chicken Spaghetti comes together really quick on the stove…no canned soup needed!  Make sure to use fresh, quality spices to season it up!  As you know, my cabinet is full of Fiesta Brand Spices & Seasonings…they are my go for seasonings and spices!  Easy to find, affordable and fresh!  Check out some of my other recipes using Fiesta Brand Seasonings!

After the squash is done, it gets mixed with the sauce and chicken, topped with cheese and in the oven it goes!  The result?  One yummy low carb dish that checks off all the flavor boxes!  Creamy, comforting, cheesy, savory with a hint of spice, this keto Chicken Spaghetti Squash Casserole is a hit!  So good in fact that The Cowboy voluntarily ate the leftovers for lunch…and dinner the next day!!  MIC DROP!

Chicken Spaghetti Casserole - GF, Low Carb and Keto Friendly

Check out these other family friendly keto and low carb meals!

Print Recipe
4.72 from 28 votes

Chicken Spaghetti Squash Casserole

Prep Time25 minutes
Cook Time20 minutes
Total Time45 minutes
Course: Main Course
Keyword: chicken spaghetti, keto, lowcarb, spaghetti squash
Servings: 8
Calories: 466kcal


  • 1 medium spaghetti squash
  • 4 cups cooked shredded chicken
  • 5 tbsp. butter
  • 1 cup diced celery
  • 1 medium onion diced
  • 1 poblano pepper diced
  • 1 bell pepper diced
  • 5 cloves garlic minced
  • 1/3 cup chicken stock
  • 1 10 oz. can diced chilis and tomatoes drained (like Rotel)
  • 1 cup heavy cream
  • 5 oz. cream cheese
  • 1 tsp. cumin
  • ½ tsp. garlic powder
  • ¼ tsp. pepper
  • 1 1/2 cup shredded Colby Jack cheese


  • Preheat oven to 400 degrees.
  • To soften the squash before cutting, microwave whole for 4-5 minutes. Be careful when removing, skin will be hot. Trim both end off the squash and cut lengthwise down the middle making two boats. Scrape and scoop seeds out and discard.
  • Drizzle the cut side of squash with olive oil and sprinkle with salt. Place cut side down on parchment lined sheet pan and roast at 400 for about 30 minutes or until tender.
  • While the squash is in the oven, melt butter in large skillet. Add onion, bell pepper, celery, poblano and cook over medium high heat for about 7 minutes or until softened. Throw in garlic cook for another 1-2 minutes. Add chicken stock and tomatoes and chilis and continue to cook till stock is reduced by half. You should have about 3 tablespoons of liquid left. Add the cream to the veggies and simmer till reduced and thickened. Remove from heat and place veggie mixture in a large mixing bowl.
  • Add cream cheese, salt, pepper, garlic, and cumin. Stir till combined and cream cheese is melted.
  • After 30 minutes, remove squash from oven and carefully flip over. The squash should be tender on top but not completely done all the way through. Using a fork remove the spaghetti squash from the peel. If there is excess moisture from the cooked squash, you will want to place the squash on some paper towels to remove the moisture.
  • Lower the oven temperature to 350 degrees. Gently mix the squash into the veggie mixture. Then, gently stir in 1/2 cup of the shredded cheese and the chicken.
  • Put the squash and chicken mixture into a greased casserole dish or 9×13 pan. Top with remaining cheese and bake at 350 for 20 minutes or until warmed through and cheese is melted and bubbly. Let sit 10 minutes before digging in!


Calories: 466kcal | Carbohydrates: 5g | Protein: 26g | Fat: 37g | Sodium: 385mg | Potassium: 375mg | Fiber: 1g | Sugar: 3g | Calcium: 236mg | Iron: 1.7mg

Nutrition facts are approximate and will vary depending on the ingredients used. Carbs from sugar alcohols have been excluded since they have shown to have no impact on blood sugar.

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11 thoughts on “Chicken Spaghetti Squash Casserole”

  • 5 stars
    Fantastic! Hubby loved this recipe and requested it again with more hot chilies. We added some Valentina hot sauce to spice it up and it added a good amount of kick! Also, how many cups of spaghetti squash did you use? My carb count was a little high cause I think I used too much.

    • 5 stars
      Hi Sara – Glad you liked the recipe!! I used a spaghetti squash that was about 3 pounds, so about 4 cups. The serving size and the amount of carbs per serving can be adjusted based on the size of your squash.

  • I’ve spent so much hard work and time on this folllowing directions to an T. I took it out after 3 hours of sitting in closed oven. It’s extremely jiggly! Like, the center is liquid. Is it supposed to be like this?!

    • It almost sounds like you making a cheesecake! Just in case..I wouldn’t say it should be jiggly, but your just wanting to heat everything together. Everything is cooked when it goes into the oven. It shouldn’t need more than 30 minutes in the oven to get warm and bubbly. The casserole sits for about 10-15 minutes after it gets taken out of the oven and this lets everything setup. It should not take three hours…It sounds like possibly your squash had some excess liquid. You can eliminate that next time by pressing it with some paper towels. Hope this helps!

  • The directions mention tomatoes, but they aren’t on the ingredient list. I’m guessing you adjusted this at some point. Should I skip tomatoes? And if not, what kind did you use? Can’t wait to make this. It sounds delicious!

    • Hi Lucy – The recipe calls for diced chilis and tomatoes, like Rotel. I use the Rotel Brand or the store version, both work just fine! Don’t skip the chili and tomato…it adds spice and flavor! Hope you enjoy!

  • 5 stars
    This recipe was so good! We added it to one of our favorites for dinner. We like it spicy so we did the hot rotel and it was perfect. Thank you!

  • 5 stars
    My husband gave this a big thumbs up! Loved the creamy yet spicy flavours. I added dried chili peppers for the heat, didn’t have canned or Rotel tomatoes so used a couple of large ripe fresh tomatoes, that worked well. Will definitely make this again, thanks.

  • 5 stars
    I made this today while I was making a pork tenderloin. Had a spoonful. With our dinner tonight. Hubby kept asking for more. LOL I told him, it had to marinate in the fridge for 24 hours. I’ll stir all the melted cheese and add more cheese to bake it warm tomorrow. Was excellent as a side dish tonight. I never had spaghetti squash before. Thank you for teaching
    me how to fix it and that I love it!

  • 5 stars
    This was my first recipe for spaghetti squash and is absolutely delicious! I eliminated the cumin, celery, and peppers, just because I didn’t have them., but without them, it was fabulous!!! Thank you so much for this recipe!!

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