Combine buttermilk and hot sauce in a large bowl. Submerge chicken, cover, and refrigerate at least 2 hours or up to 8 hours.

Preheat oven to 400°F (200°C). Whisk flour, salt, paprika, garlic powder, onion powder, black pepper, and cayenne. Press each piece of chicken firmly into the flour mixture, shake off excess.

Place a wire rack on a rimmed baking sheet. Arrange chicken skin side up, spaced apart. Mist generously with oil.

Bake 40 to 45 minutes, rotating the pan at 30 minutes and misting again if dry, until the crust is deep amber and internal temperature reaches 165°F (74°C) for breasts or 175°F to 180°F (79°C to 82°C) for dark meat.

Rest on the rack 5 minutes, then transfer to a platter and serve hot.