Preheat your oven to 350°F. Lightly grease a 9x13 casserole dish.
In a large bowl, combine shredded chicken, instant rice, cream of chicken soup, sour cream, onion and pepper blend, diced tomatoes with chilies, chicken broth, fajita seasoning, and half of the cheese. Mix until fully combined.
Spread the mixture evenly into the prepared casserole dish. Cover with foil and bake for 35 minutes.
Remove the foil, sprinkle the remaining cheese over the top, and bake uncovered for an additional 10 minutes, or until the cheese is melted and bubbly.
Allow the casserole to rest for 5 minutes before serving.