Prep the celery: Wash the celery well, trim the ends, and cut into short “boats.” For extra scoop space, use the larger outer stalks.
Pat dry so the filling sticks.
Mix the sauce base: In a large bowl, whisk the Greek yogurt (or softened light cream cheese), mayonnaise if using, lemon juice, garlic powder, onion powder, and a pinch of salt and pepper until smooth.
Add the buffalo sauce: Stir in 1/3 cup buffalo sauce. Taste and add more if you want extra heat or tang. The mixture should be creamy and orange, not runny.
Fold in the chicken: Add the shredded chicken and mix until evenly coated.
If it looks too thick, add a splash more buffalo sauce or a spoon of yogurt.
Stir in fresh elements: Fold in the chopped green onions. If using cheddar, mix it in now for a little melty richness.
Adjust seasoning: Taste and season with additional salt, pepper, or buffalo sauce. For extra brightness, a squeeze more lemon works wonders.
Fill the boats: Spoon the buffalo chicken mixture into the celery channels, mounding slightly.
Arrange on a platter.
Finish with toppings: Sprinkle with crumbled blue cheese or feta if you like. Drizzle lightly with ranch or blue cheese dressing, or serve it on the side.
Serve: Enjoy immediately for the best crunch. Add a few carrot sticks on the side for color and extra dip action.