Begin by marinating the chicken. In a bowl, combine buttermilk, garlic powder, onion powder, paprika, salt, and black pepper. Add the chicken breasts and ensure they are fully submerged. Cover and refrigerate for at least 1 hour, or up to overnight for best flavor.

In a shallow dish, mix the flour with a pinch of salt and pepper. In another shallow dish, place the breadcrumbs.

Remove the chicken from the buttermilk marinade, allowing excess to drip off. Dredge each piece in the flour mixture, then dip it back into the buttermilk, and finally coat it with breadcrumbs, pressing gently to adhere.

In a large skillet, heat about 1 inch of vegetable oil over medium-high heat until it reaches 350°F. Carefully add the breaded chicken to the hot oil, cooking for 5-7 minutes on each side, or until golden brown and cooked through (internal temperature should reach 165°F). Remove and drain on paper towels.

While the chicken is frying, prepare the sauce by mixing mayonnaise, ketchup, Worcestershire sauce, garlic powder, sugar, salt, and pepper in a small bowl. Adjust seasoning to taste.

To assemble the sandwiches, place a piece of fried chicken on the bottom half of each bun. Top with lettuce, pickles if desired, and a generous dollop of the sauce. Place the top half of the bun on each sandwich.