Preheat oven to 350°F (175°C) and grease a casserole dish.
In a large bowl combine shredded chicken, cream of chicken soup, and sour cream.
Add garlic powder, salt, and black pepper and mix well.
Stir in shredded cheddar cheese.
Spread the mixture evenly into the prepared casserole dish.
In a small bowl mix crushed Ritz crackers with melted butter.
Sprinkle the buttery cracker topping evenly over the casserole.
Bake for 25–30 minutes until the top becomes golden and crispy.
Let the casserole cool slightly before serving.