In a medium bowl, combine the cranberry sauce, chili sauce, orange juice, brown sugar, and garlic powder, stirring until the brown sugar dissolves and the mixture is smooth and well combined. I like to use whole berry cranberry sauce here because it gives the sauce better texture and looks more appealing than jellied—the berries break down slightly as it cooks and create a lovely chunky consistency. Taste the sauce and adjust sweetness or tanginess as needed before moving to the slow cooker.

Add the meatballs to your slow cooker in an even layer, then pour the sauce from Step 1 over them, gently stirring to coat all the meatballs evenly. Make sure the meatballs are mostly submerged or coated so they heat through evenly and absorb the flavors from the sauce.

Cover the slow cooker and cook on LOW for 4 hours, stirring gently once or twice halfway through if you're checking on it. Just before serving, sprinkle the freshly chopped parsley over the meatballs for a bright pop of color and fresh flavor. I find that adding the parsley at the end rather than during cooking keeps its vibrant green color and fresh taste—if it cooks for too long, it loses both.