1. Preheat your oven to 375 F (190 C). Lightly grease a 9×13 inch baking dish with cooking spray or a little butter to prevent sticking.

2. In a large mixing bowl, whisk together the condensed cream of chicken soup, cream of mushroom soup, milk, sour cream, onion powder, garlic powder, and black pepper until the mixture is smooth and well combined.

3. Add the shredded or diced cooked chicken and the cooked white rice to the creamy soup mixture. Stir gently until all the chicken and rice are evenly coated with the sauce.

4. Fold in 3/4 cup of the shredded cheddar cheese into the chicken and rice mixture. Stir just until the cheese is distributed throughout.

5. Pour the entire mixture into your prepared 9×13 inch baking dish and spread it out evenly with a spatula.

6. In a small bowl, combine the crushed butter crackers with the 2 tablespoons of melted butter. Stir until the cracker crumbs are thoroughly coated with butter.

7. Sprinkle the remaining 1/4 cup of shredded cheddar cheese over the casserole, then evenly distribute the buttered cracker crumbs on top. Place the dish in the preheated oven and bake for 25-30 minutes, or until the casserole is bubbly around the edges and the topping is golden brown and crispy.

8. Once baked, remove the casserole from the oven and let it rest for 5-10 minutes before serving.