Preheat your oven to 350°F (175°C).
In a large bowl, combine cooked rice, diced chicken, and broccoli florets.
Add cream of chicken soup, milk, garlic powder, onion powder, salt, and pepper.
Stir until all ingredients are well mixed.
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.
Bake in the preheated oven for 25-30 minutes until bubbly.
Remove from oven and let sit for 5 minutes before serving.
Enjoy your delicious casserole warm!