Creating Chicken Fajita Casserole is straightforward and enjoyable. Follow these easy steps to bring your casserole to life:

1. Preheat the oven: Set your oven to 350°F (175°C) to prepare for baking.
2. Cook Chicken: In a large skillet, heat olive oil over medium heat. Add the diced chicken, seasoning it with salt and pepper. Cook until the chicken is browned and cooked through, about 5-7 minutes.
3. Add Vegetables: Toss in the sliced onion and bell peppers. Cook for an additional 5 minutes, stirring occasionally, until the vegetables are tender.
4. Season and Combine: Stir in the taco seasoning, diced tomatoes with green chilies, and black beans, mixing well to combine the flavors. Cook for another 2-3 minutes.
5. Combine Rice: In a large mixing bowl, combine the cooked rice with the chicken and vegetable mixture, ensuring everything is evenly distributed.
6. Transfer to Casserole Dish: Pour the combined mixture into a greased 9×13-inch casserole dish, spreading it out evenly.
7. Top with Cheese: Sprinkle the shredded cheddar cheese generously over the top of the casserole.
8. Bake: Place the casserole in the preheated oven and bake for 30-35 minutes, or until the cheese is bubbly and golden.
9. Garnish: Once baked, remove from the oven and let it cool for a few minutes. Garnish with fresh cilantro, if desired.
10. Slice and Serve: Cut into portions and serve warm, adding a dollop of sour cream if you prefer.