Preheat the oven to 425°F (220°C) and line a baking sheet with parchment paper or a silicone baking mat.
Place the cut chicken pieces in a bowl and pour the buttermilk over them; season with 1/2 tsp salt and 1/4 tsp pepper, toss to coat, and let sit 10 minutes while preparing coatings.
In a shallow bowl combine the flour, garlic powder, paprika, and the remaining 1/2 tsp salt and 1/4 tsp pepper.
In another shallow bowl mix the panko breadcrumbs with the olive oil or melted butter until evenly moistened.
Working with one piece at a time, dredge each chicken piece in the seasoned flour, shake off excess, dip back in the buttermilk, then press into the panko to fully coat.
Arrange the coated nuggets on the prepared baking sheet in a single layer without crowding, leaving a little space between pieces.
Bake for 18–22 minutes, flipping once halfway through, until the nuggets are golden brown and an instant-read thermometer inserted into the thickest piece reads 165°F (74°C).
Remove the nuggets from the oven and let rest 2–3 minutes, then serve hot with assorted dipping sauces.