Preheat charcoal or gas grill to medium-hot. Combine barbecue sauce with chipotle chiles; set aside.
Brush tenderloin with garlic-flavored oil. Grill approximately 25 minutes or until internal temperature reaches 150°F.
Brush tenderloin generously with barbecue sauce mixture and grill a couple more minutes, about one minute per side. Let tenderloin stand 5 minutes before slicing.