Preheat oven: Preheat oven to 375°F (190°C). Grease a 9×13-inch baking dish.

Prepare filling:

In a large bowl, combine cream of chicken soup, sour cream, milk, garlic powder, onion powder, salt, and pepper. Mix well.
Add cooked chicken and 1 cup of shredded cheddar cheese. Stir to combine.
Prepare biscuits: Cut refrigerated biscuits into quarters. Gently fold them into the chicken mixture until coated.

Assemble casserole: Pour the mixture into the prepared baking dish, spreading evenly. Sprinkle with the remaining 1/2 cup of cheddar cheese.

Bake: Bake in preheated oven for 30-35 minutes, or until biscuits are puffed and golden brown, and cheese is melted and bubbly.

Brush with butter: Remove from oven and brush the tops of the biscuits with melted butter.

Serve: Let cool slightly before serving. Garnish with fresh parsley or chives, if desired.

Enjoy your delicious Chicken Biscuit Casserole!