Preheat your oven to 350°F (175°C).
In a large mixing bowl, combine the uncooked rice, chicken broth, cream of mushroom soup, garlic powder, onion powder, salt, and black pepper. Whisk until well blended.
Add the frozen mixed vegetables and the bite-sized chicken pieces to the mixture. Stir until everything is evenly coated.
Lightly grease the casserole dish with olive oil, or spray with non-stick cooking spray.
Pour the chicken and rice mixture into the prepared casserole dish. Spread it evenly.
Cover the casserole dish with aluminum foil and bake in the preheated oven for 30 minutes.
After 30 minutes, remove the foil, stir the casserole gently, and return it to the oven for an additional 15 minutes, or until the chicken is cooked through and the rice is tender.
If using, sprinkle the shredded cheddar cheese on top during the last 5 minutes of baking, allowing it to melt.