Heat the oven to 400F. Scrub and dry the sweet potatoes, rub them with the olive oil and coarse salt, and pierce each one three or four times with a fork.

Bake on a foil-lined sheet pan for 45 to 55 minutes, until a knife slides into the center with no resistance. Do not microwave them, the flesh holds water and the filling will not set. Cool 10 minutes.

Halve each potato lengthwise and scoop the flesh into a large bowl, leaving a ¼ inch wall of flesh clinging to each skin so the shells hold their shape.

Add the butter, softened cream cheese and Greek yogurt to the hot flesh and mash until smooth. Mashing while the flesh is hot melts the dairy in evenly.

Stir in the buffalo sauce, garlic powder, onion powder, salt and pepper, then fold in the shredded chicken with about five gentle turns so the strands stay whole.

Spoon the filling back into the eight shells, leveling it just below the edge of the skin without packing it down. Set them on the sheet pan.

Scatter the Monterey Jack and blue cheese over the tops and bake at 375F for 15 to 20 minutes, uncovered, until hot through and fully melted.

Broil 2 minutes, watching closely, until the tops are spotty gold. Finish with the sliced scallions, celery and the reserved tablespoon of buffalo sauce.