Preheat Oven: Preheat your oven to 375°F (190°C). Grease a 9x13-inch casserole dish.
Prepare the Rice Base: Spread the uncooked rice evenly in the bottom of the prepared casserole dish.
Mix the Sauce: In a large mixing bowl, whisk together the cream of mushroom soup, cream of chicken soup, chicken broth, sour cream, garlic powder, onion powder, salt, and black pepper.
Assemble the Casserole: Pour half of the sauce mixture over the rice, spreading it evenly. Arrange the chicken pieces on top of the rice and pour the remaining sauce over the chicken.
Add Cheese and Butter: Sprinkle the Parmesan cheese over the casserole, then drizzle the melted butter on top.
Cover and Bake: Cover the dish tightly with aluminum foil and bake in the preheated oven for 35 minutes. Remove the foil, sprinkle the mozzarella cheese on top, and bake uncovered for an additional 10-15 minutes, or until the cheese is melted and bubbly and the rice is tender.
Garnish and Serve: Let the casserole rest for 5 minutes before serving. Garnish with chopped parsley, if desired.