Preheat the oven to 400°F. Line a rimmed baking sheet with parchment paper.
Add the ground chicken, breadcrumbs, egg, onion, garlic, Worcestershire sauce, salt, paprika, garlic powder, black pepper, and parsley to a large bowl.
Mix gently until just combined. Do not overmix.
Shape the mixture into approximately 30 one-inch meatballs and arrange them on the prepared baking sheet.
Bake for 15 to 18 minutes, or until the meatballs reach an internal temperature of 165°F.
Meanwhile, combine the ketchup, grape jelly, chili sauce, vinegar, Worcestershire sauce, and garlic powder in a large skillet.
Cook over medium-low heat, stirring regularly, until the sauce is smooth and gently simmering.
Add the baked meatballs to the sauce and stir until evenly coated.
Simmer over low heat for five to eight minutes.
Serve warm with cocktail picks, or transfer the meatballs to a slow cooker set to warm.