In a large skillet, combine the canned jellied cranberry sauce, chili sauce, brown sugar, garlic powder, and black pepper. Heat over medium heat for about 5 minutes, stirring continuously until the mixture is smooth and has thickened slightly.

Carefully stir in the pre-cooked frozen meatballs until they are well-coated in the luscious sauce. Lower the heat to medium-low, cover the skillet, and let the meatballs simmer for 15 to 20 minutes.

Once the meatballs are heated through, take them off the heat and transfer them to a serving bowl or a slow cooker set to warm. Garnish with chopped parsley or rosemary if desired.