Preheat and Prepare: Start by preheating your oven to 350°F and lightly greasing your baking dish with non-stick spray.
Combine Ingredients: In a large bowl, mix the chicken, rice, cream of chicken, sour cream, onion, bell pepper, tomatoes with chilies, chicken broth, fajita seasoning, and half of the cheese until well combined.
Assemble the Casserole: Transfer the mixture to your prepared dish, spreading it evenly. Cover the dish tightly with aluminum foil.
Bake: Place the casserole in the oven and bake for 35 to 45 minutes, or until the rice is tender.
Final Touch: Remove the casserole, sprinkle the remaining cheese on top, and return it to the oven until the cheese melts beautifully.