Marinate the chicken breast in half of the pesto for at least 1 hour. The chicken tastes best when marinated overnight.
Remove the chicken from the marinade and grill on medium high for 5 minutes per side. You should be able to see grill marks and the juices should run clear. If the chicken is thicker it will need additional time.
Take the chicken breasts off the grill and season with a pinch of salt and pepper. When chicken has cooled, plate on a bed on fresh lettuce greens alongside 2-3 pieces of sliced mozzarella. Top with the other half of the pesto and balsamic glaze and serve! We added half an avocado for a slightly more filling meal.