Preheat oven to 375°F (190°C) and lightly grease a 9x13 inch baking dish.
In a large mixing bowl, combine the condensed cream of chicken soup, sour cream, milk, garlic powder, onion powder, and black pepper.
Add the shredded chicken, cooked pasta, and 1.5 cups of the shredded cheddar cheese to the bowl, stirring until all components are thoroughly coated.
Transfer the mixture to the prepared baking dish and spread into an even layer.
In a small bowl, toss the crushed crackers with the melted butter until evenly moistened.
Top the casserole with the remaining 0.5 cup of cheddar cheese followed by the buttered cracker crumbs.
Bake for 25 to 30 minutes until the edges are bubbling and the cracker topping has reached a golden brown color.
Allow the casserole to rest for 5 minutes at room temperature before serving.