Slice the chicken breasts into 3 cm pieces and mix with half the lime juice and zest, allow to marinate for about 10 minutes.
Cut the tomatoes and mozzarella into 2 cm slices.
Separate the lettuce and finely shred the smaller leaves, chop the cucumber.
Grill the chicken on a hot grill pan for 5 minutes each side.
Mix together the remaining lime juice and zest with the mayonnaise and sweet chilli.
Lay the chicken alternately with the tomato, bocconcini and basil, serve on a large lettuce leaf with shredded lettuce and cucumber.