Preheat the oven to 400°F. Line a rimmed baking sheet with parchment paper.
Add the ground chicken, egg, panko, garlic, parsley, garlic powder, salt, black pepper, and ¼ cup buffalo sauce to a large bowl.
Mix gently until evenly combined. Let the mixture rest for 5 minutes.
Scoop and roll the mixture into approximately 24 meatballs.
Arrange the meatballs on the prepared baking sheet, leaving space between them.
Bake for 18 to 22 minutes, or until the centers reach 165°F.
Warm the remaining ¾ cup buffalo sauce. Stir in melted butter when using.
Transfer the baked meatballs to a bowl and toss gently with the warm buffalo sauce.
Garnish with parsley and serve warm with ranch dressing, celery sticks, and carrot sticks.