For the meatballs: Preheat the oven to 400 degrees F. Line a baking sheet with a silicone mat or parchment paper covered with cooking spray.
Combine the chicken, breadcrumbs, celery, hot sauce, egg, scallion, garlic and some salt and pepper in a bowl. Gently mix until well combined, being careful not to overmix. Using a tablespoon measure, remove scoops of the mixture, roll into balls and put onto the prepared baking sheet. Bake until cooked through and browned, about 15 minutes.
For the sauce. Meanwhile, in a saute pan over medium-low heat, melt the butter with the hot sauce, stirring to combine. Once the meatballs are cooked, add to the sauce and toss to coat well.
Transfer the meatballs to a platter. Sprinkle over the gorgonzola and celery leaves. Serve with the celery stalks and leaves on the side, as well as some toothpicks to skewer the meatballs as they are devoured.