Preheat your oven to 350°F (175°C).
In a large mixing bowl, combine the shredded chicken, broccoli, and cooked rice.
In another bowl, mix the cream of chicken soup and milk until smooth.
Add garlic powder, onion powder, salt, and pepper to the soup mixture.
Pour the soup mixture over the chicken and rice, stirring to combine.
Fold in half of the shredded cheddar cheese.
Transfer the mixture to a greased baking dish.
Top with the remaining cheddar cheese and optional breadcrumbs.
Bake in the preheated oven for 25-30 minutes, or until bubbly and golden.
Let it cool for a few minutes before serving.