Preheat your oven to 350°F (175°C).
In a large mixing bowl, combine cooked rice and broccoli florets.
Add chopped onions, sour cream, and milk to the mixture.
Stir in cream of mushroom soup until well combined.
Season with salt, pepper, garlic powder, and paprika.
Fold in half of the shredded cheddar cheese.
Transfer the mixture to a greased baking dish.
Top with the remaining cheddar cheese.
Bake in the preheated oven for 25-30 minutes or until bubbly.
Let cool for a few minutes before serving.