Preheat oven to 400°F.In a 9×13-inch baking dish, combine onion, red bell pepper, uncooked rice, fajita seasoning, and cayenne pepper.In a separate bowl, whisk together chicken broth, green chilies, tomato paste, and olive oil until smooth.Pour the liquid mixture into the baking dish and stir to combine with the rice and vegetables.Stir in shredded chicken, black beans, and corn until evenly distributed.Cover the dish tightly with foil and bake for 65–70 minutes, or until rice is cooked and liquid is absorbed.Remove foil, top with shredded Monterey Jack cheese, and return to the oven for 5–10 minutes until cheese is melted and golden.Let rest for 5–10 minutes before serving. Optional toppings include salsa, cilantro, or sliced avocado.