Preheat your oven to 350°F (175°C).
In a large mixing bowl, combine the shredded chicken, uncooked rice, cream of chicken soup, cream of mushroom soup, chicken broth, milk, frozen mixed vegetables, onion powder, garlic powder, and salt and pepper. Stir well until all ingredients are evenly mixed.
Transfer the mixture into a greased 9x13 inch baking dish, spreading it out evenly.
Cover the baking dish tightly with aluminum foil to lock in moisture.
Bake in the preheated oven for 45 minutes.
After 45 minutes, remove the foil, stir the casserole gently, and then sprinkle the shredded cheese on top.
Return the dish to the oven (uncovered) and bake for an additional 15 minutes or until the cheese is melted and bubbly.
Remove from the oven and let it sit for about 5 minutes before serving. This will allow the casserole to set slightly.