01 - Preheat oven to 375°F. Grease a 9x13-inch baking dish lightly with nonstick spray.
02 - In a large mixing bowl, whisk together condensed cream of chicken soup, milk, garlic powder, onion powder, and 2 cups shredded cheddar cheese until smooth.
03 - Fold chicken breast pieces, cooked rice, and broccoli florets into the cheese sauce. Stir gently to coat ingredients evenly.
04 - Pour mixture into prepared baking dish. Use a spatula to distribute ingredients evenly.
05 - Sprinkle remaining 1 cup shredded cheddar cheese evenly over the surface.
06 - Bake uncovered on center rack for 30–35 minutes, until bubbly and cheese is lightly golden.
07 - Remove from oven and let rest 10 minutes for easier portioning.