Heat the olive oil in a medium saute pan over medium heat. Add the onion and saute until soft and translucent, 5 to 8 minutes. Let cool.
In large bowl, combine the buttermilk, torn bread and 2 tablespoons of the hot sauce and mix to form a paste. Add the ground chicken, breadcrumbs, ranch dressing mix, egg and 1/2 cup of the diced celery and mix with your hands until combined. Toss in the blue cheese crumbles and mix gently again. Refrigerate for 30 minutes.
Form the meatball mixture, rolling into a uniform ball and place on the prepared baking sheet. Continue until you have 16 balls. Make sure to wash your hands in cold water a few times between rolling to keep the meatballs from sticking to your hands. Bake the meatballs until lightly browned, 15 to 20 minutes.