Spray the bottom of your slow cooker lightly with cooking spray. Add frozen meatballs to the bottom of pot.
In a large bowl stir together cranberry sauce, cocktail sauce, brown sugar, water, and barbecue sauce and pour over meatballs.
Cook on LOW for 4-6 hours or HIGH for 2-3 hours.
Serve warm garnished with chopped green onions, if desired.
