Rinse chicken and pat dry.
Pierce surface of meat with a fork and place in a resealable plastic bag with pureed mango, balsamic vinegar, oil, salt and pepper.
Seal bag and marinate in the refrigerator for several hours or overnight.
Combine all chutney ingredients in a medium saucepan and stir well.
Bring to a boil; reduce heat and simmer, covered, for 20 minutes.
Uncover and simmer over low heat for a few minutes more to cook off excess liquid; let cool. (May be made up to 2 weeks ahead. Store tightly covered in the refrigerator.)
When ready to serve, remove chicken from marinade and grill over medium coals for about 5 to 7 minutes on each side minutes, or until cooked through.
Serve with Mango Chutney.
Tip: Leftover chutney is delicious when spread on cold or grilled ham sandwiches.