Preheat your oven to 350°F (175°C).
In a large mixing bowl, combine the cooked rice, shredded chicken, and broccoli florets.
In a separate bowl, mix the cream of chicken soup, milk, garlic powder, onion powder, salt, and pepper until smooth.
Pour the soup mixture over the rice, chicken, and broccoli, stirring until everything is well combined.
Transfer the mixture to a greased 9x13 inch casserole dish.
Sprinkle shredded cheddar cheese evenly over the top.
If desired, add breadcrumbs for extra crunch.
Cover the dish with aluminum foil and bake for 20 minutes.
Remove the foil and bake for an additional 10 minutes, or until the cheese is bubbly and golden brown.
Let it cool for a few minutes before serving.