Preheat oven to 350°F (175°C). Lightly grease a 9x13-inch baking dish with butter or cooking spray.

In a large mixing bowl, combine the cooked chicken, cream of chicken soup, sour cream, and milk. Stir until smooth and creamy.

Add the frozen vegetables, garlic powder, onion powder, salt, and pepper. Mix until everything is evenly distributed.

Cut each biscuit into quarters. Add the biscuit pieces to the chicken mixture and fold them in, making sure each piece gets completely coated with the creamy sauce.

Pour the entire mixture into the prepared baking dish and spread evenly. Sprinkle shredded cheese uniformly over the top.

Cover the dish tightly with aluminum foil and bake for 20 minutes.

Remove foil and continue baking for an additional 10 to 15 minutes, until biscuits are puffed, golden brown, and cooked through.

Brush with melted butter if desired. Let rest for 5 minutes before serving.