Rinse and drain the navy beans thoroughly to remove excess sodium, then cut the chicken thighs into 1-inch bite-sized pieces. In a small bowl, whisk together all the dry spices: chili powder, seasoned salt, cumin, smoked paprika, garlic powder, onion powder, pepper, cayenne pepper, and dried oregano. This ensures even distribution of flavors throughout the dish. I like to combine spices separately because it helps them distribute evenly without clumping when mixed with liquid.

Preheat your oven to 375°F and lightly grease a 9x13 inch baking dish. In the prepared dish, combine the cream of chicken soup, chicken broth, and the spice mixture from Step 1, stirring well to dissolve the spices. Add the prepared chicken pieces, rinsed navy beans, canned tomatoes with green chilies (with their liquid), mexicorn (drained), and uncooked white rice. Stir everything together thoroughly to ensure the rice is distributed evenly and all ingredients are fully incorporated.

Cover the baking dish tightly with foil to trap steam, which helps cook the rice evenly and keeps the chicken moist. Bake in the preheated 375°F oven for 60-70 minutes, until the rice is tender and the chicken is cooked through. The foil is crucial here—it creates a steaming environment that prevents the top from drying out while everything cooks together.

Carefully remove the foil from the hot dish and give the entire casserole a good stir to redistribute the rice and ingredients evenly. Check that the rice is tender and the chicken is fully cooked. Sprinkle the freshly shredded cheddar cheese evenly over the top of the casserole. Fresh-shredded cheese melts much more smoothly than pre-shredded varieties, which contain anti-caking agents that can make it clumpy.

Turn your oven to broil on high heat and position the rack about 6 inches from the heat source. Place the casserole under the broiler for 2-3 minutes, watching carefully, until the cheese is fully melted and begins to lightly brown on top. Remove from the broiler immediately once the cheese reaches the desired doneness to avoid burning.

Let the casserole rest for 5 minutes before serving. This allows the cheese to set slightly and makes serving much cleaner. Divide into bowls and serve with your favorite toppings like sour cream, fresh cilantro, diced onions, or additional shredded cheese if desired.