Preheat your oven to 400°F (200°C).

In a small bowl, combine the chili powder, cayenne pepper, garlic powder, smoked paprika, onion powder, ground cumin, dried oregano, salt, and black pepper.

In a 9x13-inch baking dish, mix together the chopped white onion, diced red bell pepper, uncooked brown rice, and the prepared spice mixture.

In a large bowl, whisk together the chicken broth, chopped green chilies, olive oil, and tomato paste until smooth.

Pour the liquid mixture into the baking dish over the rice and vegetable mixture, stirring thoroughly.

Fold in the drained corn, rinsed black beans, and shredded chicken into the baking dish, mixing gently.

Cover the baking dish with aluminum foil and bake for 65-70 minutes, until the rice is tender.

Remove the foil and sprinkle shredded cheddar cheese over the top, then return to the oven and bake uncovered for an additional 5-10 minutes.

Let the casserole cool for about 5-10 minutes before serving, topping with cilantro, green onions, avocado, or salsa.