Preheat oven to 350 degrees F. Spray a casserole dish with nonstick cooking spray.
Bring a pot of water to a boil. Cook and drain the egg noodles according to the directions on the bag.
Add the cream of chicken soup, sour cream, skim milk, garlic powder, onion powder, and black pepper to a small mixing bowl. Use a whisk to combine the ingredients.
To a large mixing bowl, add the shredded chicken, vegetables, and sauce. Mix the ingredients together.
Use a rubber spatula to fold in the noodles. Once all of the ingredients are combined pour them into the baking dish. Use the rubber spatula to level the top for even cooking.
Top the casserole with the shredded cheese.
Place the Ritz crackers in a ziplock bag and seal it closed. Use a rolling pin to crush the crackers.
Sprinkle the crushed Ritz crackers on top of the casserole.
Cover the casserole dish and bake for 20 minutes. Remove the cover and bake an additional 10 minutes.
Let the casserole cool for a couple of minutes then serve.