Prep Your Dish: Lightly coat a 9×13-inch casserole dish with nonstick cooking spray.
Combine the Filling: In a large mixing bowl, add the shredded chicken, uncooked instant rice, cream of chicken soup, sour cream, frozen onion and bell pepper blend, undrained diced tomatoes with chilies, chicken broth, fajita seasoning, and half the shredded cheese. Stir until everything is well combined.
Assemble the Casserole: Transfer the chicken and rice mixture into your prepared baking dish and spread it out evenly.
Bake (Covered): Cover the casserole dish with aluminum foil. Bake in a preheated oven at 350°F (175°C) for 35 minutes.
Top with Cheese and Finish Baking: Remove the foil, sprinkle the remaining cheese evenly over the top, and bake uncovered for another 10 minutes, or until the cheese is completely melted and bubbly.
Notes
Store leftovers in an airtight container for up to 3–4 days. This casserole freezes well; cool completely, transfer to a freezer-safe container, and freeze for up to 3 months.