Preheat your oven to 375°F (190°C) and grease a 9x13 inch baking dish with butter.
In a large mixing bowl, combine the shredded chicken, rice, broccoli, cheddar cheese, and parmesan.
Add the cream of chicken soup, sour cream, milk, garlic powder, and onion powder. Season with salt and pepper to taste.
Mix everything until well combined. It’ll look a little messy, but that’s the magic.
Spread the mixture evenly into the prepared baking dish.
Top with an extra sprinkle of cheddar if you like things extra cheesy. (I always do!)
Bake uncovered for 25 to 30 minutes until hot and bubbly, and the top is golden in spots.
Let it cool for 5 minutes before serving. It’ll hold together better and won’t burn your tongue. (Learned that the hard way.)