In a medium saucepan, combine the cranberry sauce, brown sugar, chili powder, cumin, and cayenne pepper. Heat over medium heat, stirring occasionally, until the mixture becomes smooth and starts to bubble, about 5 minutes.

Once the sauce is heated through, gently add the fully cooked meatballs to the saucepan. Stir to coat each meatball evenly in the sauce, about 2 minutes.

Continue to cook the meatball and sauce mixture over medium heat for about 10 minutes, stirring occasionally. Taste and adjust seasoning as desired.

When the meatballs are heated thoroughly, remove the saucepan from the heat. Serve hot on a platter, garnished with fresh herbs if desired.