Whisk together basil, garlic clove, chili pepper, lime juice, sesame oil and nuoc mam sauce. Marinate the meat cubes for at least four hours, turning frequently to the other side.
For the sauce, stir all ingredients together thoroughly, pour sauce into a suitable bowl and place on the table.
Divide meat evenly among four skewers. Cook on a charcoal grill or a heated electric grill, brushing frequently with the marinade and turning to the other side.