Preheat your oven to 350°F (175°C).
In a large mixing bowl, combine shredded chicken, broccoli florets, and cooked rice.
Add cream of chicken soup, milk, garlic powder, onion powder, salt, and pepper to the mixture.
Stir in 3/4 cup of shredded cheddar cheese and mix well.
Transfer the mixture into a greased 9x13-inch baking dish.
Spread the remaining cheddar cheese on top of the chicken and broccoli mixture.
Sprinkle breadcrumbs evenly over the cheese.
Bake in the preheated oven for 25-30 minutes, or until the top is golden brown.
Allow the casserole to cool for 5 minutes before serving.
Serve warm and enjoy your delicious chicken broccoli casserole!