Set your oven to 350°F (175°C) and grease a 9x13-inch baking dish lightly.
In a large bowl, mix together the cooked chicken, cream of chicken soup, sour cream, milk, frozen vegetables, garlic powder, onion powder, salt, and pepper until the mixture is smooth and well combined.
Gently fold the quartered biscuit dough into the mixture, making sure each piece is coated.
Transfer the entire mixture into the prepared baking pan and evenly distribute the shredded cheese on top.
Cover the dish with foil and bake it for 20 minutes.
Remove the foil then continue baking for another 10 to 15 minutes, until the biscuits have risen, appear golden, and are fully cooked.
If you like, brush melted butter over the biscuits just before serving and let the casserole cool for a few minutes to set.