Heat the oven to 425°F. Set a rack over a rimmed baking sheet and brush it with 1 teaspoon of the oil.
Pat thighs dry and toss with buttermilk in a bowl. Mix panko, Parmesan, dried herbs, garlic powder, onion powder, salt, pepper and remaining 2 teaspoons oil in a shallow dish.
Lift each thigh from the buttermilk, allowing excess to drip back into the bowl, and press both sides into the crumb mixture. Discard leftover buttermilk and crumbs that touched raw chicken.
Arrange coated thighs unfolded on the rack and bake for 25 to 30 minutes until the coating is golden and the thickest meat reaches at least 165°F.
Rest on the rack for 5 minutes before lifting with a thin spatula and serving.