In a medium bowl, combine the soy sauce, apple juice, onion, ginger, garlic, oil, bourbon, BBQ sauce, vinegar and brown sugar . Reserve and refrigerate 1/4 cup of the marinade and transfer the remainder to a Ziploc bag with the chicken. Refrigerate and marinate for at least 1 hour
Grill over medium high heat for 4 1/2 minutes per side, or until chicken is at 170 internal temp.
Simmer reserved marinade until you have desired thickness, brush over chicken after slicing.