Preheat the oven to 350°F (175°C).

In a large mixing bowl, combine cooked rice, broccoli florets, cream of mushroom soup, milk, garlic powder, onion powder, salt, and pepper. Mix until smooth.

Stir in half of the shredded cheddar cheese until it melts slightly into the mixture.

Transfer the mixture into a greased baking dish, spreading it evenly.

Sprinkle the remaining cheddar cheese over the top of the casserole.

Bake in the preheated oven for 30-35 minutes until bubbly and golden brown.

Let cool for 5-10 minutes, slice, and serve warm.