In a shallow dish, mix together the flour, garlic powder, onion powder, paprika, salt and pepper.
In a separate dish, whisk together 1/2 cup of the buttermilk and 1 tablespoon of the hot sauce.
Dip each chicken breast in the buttermilk mixture and then dredge in the flour mixture. Place on a plate or baking sheet.
Heat about 2 inches of oil in a large skillet over medium-high heat. Fry the chicken for about 4 minutes per side or until cooked through.
Remove from the skillet and place on a paper towel-lined plate to drain.
To assemble sandwiches: spread remaining tablespoon of hot sauce on one side of each bun. Top with fried chicken breast and lettuce. Drizzle remaining 1/4 cup buttermilk over each sandwich before topping with remaining buns.