Making Chicken Fajita Casserole can be easy if you follow these simple steps:

1. Preheat Oven: Preheat your oven to 350°F (175°C).
2. Sauté Vegetables: In a large skillet, heat the olive oil over medium heat. Add the sliced onion and bell peppers, sautéing until tender, about 5-7 minutes.
3. Add Chicken and Seasoning: Stir in the cooked, shredded chicken and fajita seasoning. Mix well to ensure the chicken is well-coated in spices.
4. Combine Other Ingredients: In a large bowl, combine black beans, corn, and salsa. Add the chicken mixture and stir to combine all ingredients well.
5. Layer the Casserole: In a prepared baking dish, spread half of the chicken mixture on the bottom. Sprinkle with half of the cheese. Layer the remaining chicken mixture on top, followed by the remaining cheese.
6. Bake: Place in the preheated oven and bake for 30-35 minutes or until the cheese is bubbly and golden.
7. Add Toppings: Once out of the oven, let it sit for a few minutes. Top with dollops of sour cream and any additional toppings of your choice, like jalapeños or cilantro.
8. Serve Warm: Cut into squares and serve warm.

These steps will guide you in creating this delightful Chicken Fajita Casserole effortlessly.