Preheat grill to medium-high heat.
Whisk together ketchup, vinegar, brown sugar, molasses, Worcestershire sauce, mustard, garlic powder, onion powder, pepper and water. Reserve 1/3 cup and set aside.
Combine ketchup mixture and chicken in a gallon-size slider bag or large bowl; refrigerate and marinate for at least 1 hour to overnight, turning the bag occasionally. Drain the chicken from the marinade; discard marinade.
Make drainage holes in a sheet of Reynolds Wrap(R) Non-Stick Foil with a grilling fork. Place foil sheet on grill grate with non-stick (dull) side facing up. Immediately place chicken on foil.
Add chicken to grill and cook, flipping once and basting with reserved 1/3 cup marinade until cooked through, about 10 to 12 minutes on each side