If chicken isn't an even thickness then place chicken in a large ziploc bag and seal bag. Using the flat side of a meat mallet, pound chicken to an even thickness.
Place chicken in a non-reactive dish in a single layer. In a mixing bowl whisk together remaining ingredients. Reserve 2 Tbsp of the mixture in a non-reactive, airtight container in the refrigerator. Pour remaining mixture over the chicken, cover dish and allow to marinate 8 hours or overnight in the refrigerator.
Preheat grill to medium high heat. Once preheated, brush grill lightly with olive oil. Place chicken on grill and cook (with lid closed) 5-8 minutes per side until juices run clear (cook time depends on the thickness of the chicken, internal temp should register to 160 when done), baste each side of chicken with reserved marinade during the last minute of cooking. For juicier chicken, plate chicken, cover with foil and allow to rest 5 minutes. Serve immediately.