Before You Begin
Prepare your cookware as needed. Cooking times and results may vary depending on your equipment and ingredients.
Preheat the oven to 375°F (190°C) and lightly grease a 9×13-inch baking dish.
In a large bowl, combine the cooked chicken, broccoli florets, and cooked rice. Mix gently so the ingredients remain loose and evenly distributed.
In a separate bowl, whisk together the cream of chicken soup, milk, sour cream, garlic powder, onion powder, salt, and black pepper until smooth.
Pour the sauce over the chicken mixture and fold gently until evenly coated. Stir in 1½ cups of the shredded cheddar cheese.
Transfer the mixture to the prepared baking dish and spread evenly. Sprinkle the remaining cheese over the top.
Bake for 25–30 minutes, or until the casserole is bubbly around the edges and the cheese is melted with light golden spots.
Remove from the oven and let rest for 5–10 minutes so the casserole sets before serving.