Marinate the chicken breasts in buttermilk for at least 1 hour.
Mix the flour, garlic powder, onion powder, paprika, salt, black pepper, and cayenne pepper in a bowl.
Dredge the marinated chicken in the flour mixture, coating evenly.
Heat olive oil in a frying pan over medium heat and fry the chicken until golden brown and cooked through.
Assemble the sandwich by placing the fried chicken on a bun and topping with lettuce, tomatoes, red onion, pineapple, mayonnaise, sweet chili sauce, and lime juice.
Notes
You can customize the sandwich with your favorite toppings or sauces.