Preheat oven to 375. Prepare a 9 "x 5" pan with cooking spray; set aside. In a mixing bowl, combine chicken, onions, crushed crackers, one cup ketchup, eggs, salt, and black pepper. Mix well. Place mixture into prepared pan. Spread remaining ketchup over top of the chicken mixture. Bake one hour, or until juices run clear; drain off any liquid. Allow to sit five minutes, then transfer to a serving platter. Spread meat loaf with warmed mashed potatoes.