Chicken Fajita Casserole

Make this easy chicken fajita casserole with gooey cheese for a delicious dinner that the entire family will love! It takes just 45 minutes start to finish and is amazingly versatile. Leftovers are great for lunches the next day too, a meal prep bonus!

This version of baked chicken fajitas is simple with just 6 ingredients in the actual casserole. The casserole is keto-friendly as well. Just pair it with healthy or low carb sides and enjoy. It's super easy. Why not make it for dinner tonight!

Keto Chicken Fajita Casserole

This chicken fajitas casserole comes in at just 6 net carbs per serving, from the peppers and onions. Eat it as is or team it with low carb wraps or cauliflower rice.

A casserole is a convenient way to make fajitas, but if you want a simple stove top recipe, try my Chicken Fajita Pasta. It is in a creamy sauce and perfect for a weeknight dinner.

How to Make Fajita Chicken Casserole Bake

Now let's make this easy chicken casserole. I'll show you step-by step here or jump down to the print recipe card if you prefer.

The recipe makes 6 servings.

Prep Time: 10 mins Cooking Time: 35 mins Total Time: 45 mins

Ingredients you will need to make the fajita chicken casserole:

Here is everything you need for the chicken casserole recipe.

• 1 ½ pounds boneless skinless chicken breasts or boneless chicken thighs, slice the chicken breast meat into bite sized strips
• 2 cups sliced sweet bell peppers
• 2 cups sliced sweet onions (I used Vidalia)
• 1 tablespoon fajita seasoning see below to make your own (taco seasoning or Cajun spice mix are good stand-ins too)
• 2 tablespoons olive oil, or avocado oil
• 2 cups shredded cheese, cheddar, Monterey Jack or Mexican blend

Optional Toppings for Chicken Fajita Bake:

• fresh cilantro
• diced tomatoes
• sour cream
• diced avocado or guacamole

Equipment:

large baking dish or cast iron skillet

Directions:

Preheat oven to 400 degrees F.

Drop the sliced bell peppers, onions and chicken into the casserole dish. (No need to prep the baking dish with cooking spray, there is enough oil in the mixture to avoid sticking.)

Pour on the seasoning and oil.

Note: I did not season the chicken with salt and pepper since the cheese and fajita spice combo is sufficient in saltiness for me. If you want salt and pepper seasoned chicken, go for it.

Mix well with gloved hands. If you prefer, stir together in a large bowl with a wooden spoon. Then dump into the casserole pan.

Sprinkle the shredded cheese over the top of the chicken mixture.

Bake for 35-40 minutes, until the cheese is golden brown at the edges and a thermometer inserted in center of casserole reads 165 degrees F internal temperature.

Serving with your prefered sides and toppings, or in tortilla wraps.

Serving Suggestions

Serve the fajita casserole with flour tortillas or low carb tortillas like traditional fajitas or simply with Mexican food sides. Black beans, refried beans, Spanish rice or cauliflower rice all make excellent side dishes for the fajita chicken casserole. A green salad with avocado lime ranch dressing with also make a delicious pairing.

Use your Favorite Fajita Toppings

Sour cream, guacamole, diced tomato, salsa and fresh chopped cilantro are fabulous toppings for the chicken dish. I like a splash of hot sauce, sliced green onions and a squeeze of fresh lime juice on mine too.

Variations

There are many ways to put a twist on this casserole dish. Here are just a few:

• Add crushed tortilla chips, either mixed in or sprinkled on top in the final 10 minutes of baking. Inside they soften, as a topping they add crunch.
• Make it creamy by mixing a block of softened cream cheese along with half the shredded cheddar cheese in with the sliced chicken breasts and veggies. Top with remaining cheese and add 5-10 minutes to your bake time. Make sure the cream cheese is soft so it will mix in, microwave it a few seconds if need be. A cup of Greek yogurt or sour cream would also work.
• Leftover Rotisserie chicken is a good choice if you don't want to handle raw chicken or have leftover chicken on-hand. Simply shred it and mix in. Bake time will be reduced a little thanks to the cooked chicken, but the vegetables must still be cooked. You can reduce the cooking time to 25-30 minutes for this version. This would be a good use of leftover crock pot chicken thighs or my juicy roasted chicken.
• Mix in a can of drained and rinsed black beans for added protein and fiber.

Storing Leftovers

To store remaining casserole, simply allow to cool, then cover casserole with foil or plastic wrap or scoop into an airtight container and seal. Refrigerate promptly after cooling. The chicken will be good in the refrigerator for 3-4 days.