
In a medium sized bowl, whisk the ¾ cup balsamic vinegar, ¼ cup honey, 3 cloves garlic minced, 2 tablespoons olive oil, 2 teaspoons italian seasoning, ½ teaspoon salt, and ¼ teaspoon pepper.
Add the 4 boneless skinless chicken breasts to the marinade and coat. Marinate for 30 minutes.
Meanwhile, in a small bowl, add the 1 sliced avocado, ½ cup sliced cherry tomatoes, ½ cup basil pesto, and salt and pepper to taste. Set aside.
Heat the grill to medium-high heat. Grill the chicken on each side for about 6 minutes or until cooked through and no longer pink. Top with 4 slices mozzarella cheese, pesto mixture, and ¼ cup fresh chopped basil.
In a medium-sized skillet over medium-high heat, discard the marinade, reserving ¼ cup, and add the chicken to the skillet. Cook on each side for 3-4 minutes or until the chicken is cooked to 165 degrees.
Add the reserved marinade and cook until the sauce reduces. Top with mozzarella cheese, pestomixture, and chopped basil.