Preheat an outdoor grill for medium heat and lightly oil the grate.
Rub chicken breast with olive oil and vinegar; rub on brown sugar until becomes a nice glaze coating.
Grill on the preheated grill until no longer pink in the center and the juices run clear, about 5 minutes per side; be careful not to let the brown sugar stick to the grill. An instant read thermometer inserted into the center should read at least 165 degrees F (74 degrees C).
Meanwhile, combine peaches, tomato, grapes, onion, lemon juice, and honey in a bowl; mix thoroughly.
Dice chicken; serve on top of salsa.
Grilled Chicken with Peach Salsa · Dinner Match Lab | Dinner Match Lab