Mix garlic fish sauce, sugar, and black pepper. Add to the chicken, and marinate for 1-24 hours.
Cook the vermicelli according to the package directions, usually about 2 minutes. Drain and rinse with cold water.
Grill chicken on the barbecue until fully cooked.
Place noodles in a bowl, and top with chicken, lettuce, basil, and mint. Cover with daikon, carrots, and liquid from the nuoc cham.