Place the frozen meatballs in the slow cooker. For easy cleanup, line the slow cooker with a disposable liner if desired.
Pour in the barbecue sauce, Kentucky bourbon, honey, and sweet chili sauce. Season with garlic powder and red pepper flakes to taste, then stir until the meatballs are evenly coated.
Cover and cook on Low for about 4 hours, stirring once or twice during cooking.
Give the meatballs a final stir before serving and adjust the seasoning if needed.
Garnish with chopped parsley and serve warm.
Notes
Stir the meatballs once or twice while cooking so they're evenly coated in the sauce.
Use your favorite barbecue sauce to customize the flavor.
Add extra red pepper flakes or a splash of hot sauce for more heat.
Let the sauce simmer uncovered for the last 20–30 minutes if you'd like it a little thicker.
Keep the slow cooker on the Warm setting for serving.