Mix together cooked and diced chicken, cooked egg noodles, sour cream, cream of chicken soup, cheddar cheese, and mozzarella cheese. Put chicken and noodle mixture into a baking dish In a separate mixing bowl, stir together crushed Ritz crackers and melted butter Sprinkle cracker crumbs on top of noodle mixture Bake for about 25 minutes, until the crackers are crispy and the cheese is melted and bubbly