Line bottom of baking dish with crushed cracker. Alternate layers of chicken, drained peas (cooked first); salt, pepper, onion and maccaroni. Top all with cream of chicken soup (warm in a pan first and mix with 1 cup milk) Top with crushed crackers. Bake at 350 until bubbly. Top with shreded cheese of your choice and return to the oven til the cheese melts.