1. Gather all ingredients: frozen meatballs, jellied cranberry sauce, chili sauce, and brown sugar.
2. Prepare the slow cooker or stovetop pan.
3. If using a slow cooker, add the frozen meatballs first.
4. In a bowl, mix cranberry sauce, chili sauce, and brown sugar until well combined.
5. Pour the sauce mixture over the meatballs in the slow cooker.
6. Stir to ensure the meatballs are evenly coated with the sauce.
7. Cover and cook on low for 4 hours or on high for 2 hours.
8. If cooking on the stovetop, place all ingredients in a large saucepan.
9. Heat over medium, stirring occasionally, for 20-25 minutes until the meatballs are warmed through.
10. Add optional seasonings like garlic powder, cayenne, or Worcestershire sauce for more flavor.
11. Stir occasionally to prevent sticking or burning.
12. Once fully heated, transfer to a serving dish.
13. Garnish with chopped green onions or parsley for extra freshness.
14. Serve as an appetizer with toothpicks or as a main dish over rice.
15. Store leftovers in an airtight container in the refrigerator for 3-4 days.
16. To freeze, place cooled meatballs and sauce in a freezer-safe container for later use.