Cut a slit in thickest part of chicken; insert 2 fresh basil leaves in each one. Chop remaining basil.
Whish together vinegar, mustard, garlic, salt and pepper. Whisk in oil and chopped basil.
Remove 2 tablespoons of the dressing and brush over chicken. Peel and cut potatoes into 1 inch cubes.
Blanch potatoes in boiling water for 8 minutes. Drain.
Thread potatoes and tomatoes onto separate skewers. Brush with some of the reserved dressing.
Grill or broil chicken, potato and tomato skewers. Season lettuce with remaining dressing. Arrange on plates.
Slice chicken diagonally.
Fan over lettuce with vegetables.