In a large bowl, combine buttermilk and hot sauce. Add chicken pieces, ensuring they are fully submerged. Cover and refrigerate for at least 4 hours, preferably overnight.

In a separate bowl, mix together flour, paprika, cayenne pepper, garlic powder, onion powder, salt, and black pepper.

Remove chicken from the buttermilk mixture, allowing excess to drip off. Dredge each piece in the flour mixture, pressing lightly to adhere. Place coated chicken on a wire rack and let it rest for 15 minutes.

In a large skillet, heat about 1 inch of vegetable oil over medium-high heat until it reaches 350°F.

Carefully add chicken pieces to the hot oil, cooking in batches if necessary to avoid overcrowding. Fry for about 12-15 minutes per side, or until golden brown and cooked through (internal temperature should reach 165°F). Remove and drain on paper towels.

In a small bowl, whisk together the spicy oil ingredients: hot oil from frying, cayenne pepper, brown sugar, paprika, garlic powder, and salt.

Brush the spicy oil generously over the fried chicken pieces while they are still hot.

Serve the Nashville hot chicken on slices of white bread with pickles on the side.