In a large bowl, add garlic, apple cider vinegar, mustard, lime juice, lemon juice, coconut sugar, salt, and pepper.
Whisk in the olive oil and blend until smooth.
Place chicken in oil mixture. Cover, and marinate 8 hours, or overnight.
Preheat outdoor grill for high heat. You can also use a grill pan on your stove, if desired.
Lightly oil the grill grate. Remove chicken from marinade and discard.
Place chicken on the prepared grill over direct heat. Cook 6 to 8 minutes per side, until juices run clear and reaches an internal temperature of 165 degrees F.