Preheat the oven to 400°F.
In a 9×13 baking dish, add the uncooked rice and fajita seasoning, then stir to combine.
Pour in the chicken broth and green chiles, mixing well.
Add the cooked shredded chicken, black beans, and corn, stirring to distribute evenly.
Cover the casserole dish with aluminum foil and transfer it to the oven.
Bake for 30 minutes, then check if the rice is done. If needed, cook for up to 15 minutes more. A little liquid remaining is OK, as the rice will continue to absorb it.
Once done, remove from the oven, sprinkle with cup cheese, and return to the oven for the final 5-10 minutes until melted and golden brown.
Let the casserole cool for 5-10 minutes, then serve with fresh cilantro, chopped green onion, salsa, pico de gallo, and favorite toppings like sour cream, avocado, or black olives, if desired.