Chicken Fajita Casserole
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This Chicken Fajita Casserole is loaded with onions, bell peppers, cheese and fajita seasonings. It’s a mouthwatering meal that’s low-carb and ready in just 30 minutes with easy prep!
This dish is one of our go-to recipes whenever we get cravings for chicken fajitas. It’s a quick chicken casserole dinner you can make in 30 minutes from start to finish with one pan for easy cleanup.
OK, so it’s more Tex Mex than Mexican, but it’s still loaded with delicious fajita flavors. Plus, it’s low carb and keto-friendly as well as gluten-free! There are only 327 calories and 6 grams of net carbs per serving.
Want to make it ahead for a party or potluck? No problem! It stores well in the fridge or freezer with easy reheating. So let’s get this started!
Ingredients for Chicken Fajita Casserole
Here’s what you’ll need to make it:
- Chicken breasts: You can use boneless skinless chicken breasts cut lengthwise, or chicken fillets or cutlets without cutting. Boneless skinless chicken thighs work too.
- Onion: Yellow onion or white onion, with red onion as a substitute
- Bell peppers (capsicum): Red, yellow, orange, green or a combination
- Olive oil: extra virgin olive oil or any similar oil
- Jack cheese: Shredded Monterrey Jack is best with Cheddar or Havarti as alternatives
- Cumin powder (ground cumin)
- Chili powder
- Garlic powder: Or granulated garlic or minced fresh garlic
- Paprika: Regular paprika is best, use smoked paprika only in a pinch
- Salt and pepper
- Cilantro for garnish
Don’t forget about sour cream and guacamole for serving too.
How to Make a Chicken Fajita Casserole
To make it, the key is cutting the chicken into fillet-size pieces. Using whole chicken breasts makes the baking time too long for the other ingredients, while thin strips cook too fast leaving the vegetables crisp. So cut small-to-medium chicken breasts into halves, and large breasts into thirds.
Next, place the chicken pieces in a single layer into a 9×13-inch baking dish. Add the oil, fajita seasoning and vegetables before topping with shredded cheese. Bake at 400°F for 20-25 minutes until golden and bubbly with the internal temp of the chicken pieces reaching 160°F (it’ll rise 5°F more out of the oven).
To make serving easier, you can shred the chicken pieces with two forks. Garnish with some fresh cilantro and serve hot!
It’s easy to make your own fajita seasoning, and you can store leftovers in a mason jar for future use. If you go with a storebought mix, you may want to reduce the salt in the recipe to compensate.
What to Serve with Chicken Fajita Casserole
Alternatively, you can scoop the casserole into tortillas or add some Spanish rice on the side. Don’t forget the Margaritas for drinks too!
Is this casserole keto?
Yes, this recipe has just 6 grams of net carbs per serving, making it suitable for a keto diet.
More casserole recipes:
View all Tex Mex recipes
Chicken Fajita Casserole
- 1 ½ pounds boneless skinless chicken breasts, split lengthwise, or chicken thigh (see note)
- 3 bell peppers, red, yellow or green capsicum, seeded and sliced into strips
- 1 large yellow onion, or two medium onions (or white onion)
- 1 tablespoon olive oil
- 8 oz Jack cheese, shredded, or cheddar or Havarti (2 cups)
- fresh cilantro, optional garnish
- 1 teaspoon cumin powder
- 2 teaspoon chili powder
- 1 1/2 teaspoon garlic powder
- 2 teaspoon paprika
- salt and pepper, to taste
- Preheat the oven to 400°F (200°C) with the rack in the lower middle position. Turn on the convection/forced air if available.
- Grease a 9×13” baking dish with oil and set aside. Arrange the split chicken breasts in a single layer in the prepared baking dish.
- In a small bowl, combine the cumin, chili powder, garlic powder, paprika, salt and pepper. Drizzle oil on top and sprinkle on half the fajita seasoning.
- Add the sliced onions and bell peppers on top of the chicken. Sprinkle the remaining seasoning on top.
- Top with the shredded cheese and then place the casserole in the oven. Bake for 20-25 minutes or until the chicken reaches an internal temperature of 160°F (check by inserting an instant-read thermometer into the middle of a large piece.)
- Garnish with optional cilantro and serve warm.
- Fajita Seasoning: You’ll need 2 tablespoons of seasoning if using storebought or a premade mix.
- Baking Time: Will be up to 5 minutes faster with convection turned on and using a glass or ceramic dish.
- Spicy: To make it spicy, add up to 1 teaspoon of cayenne to the seasonings and/or 1 sliced jalapeño along with the peppers.
- Make Ahead Tips: You can also make it ahead in the morning, cover with plastic wrap and refrigerate for up to one day before baking (add 10 minutes to baking time in this case). After baking, cool completely, cover with plastic wrap and refrigerate for up to 3 days. You can also freeze individual portions in airtight containers for up to 3 months.
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