, excess fat trimmed
PREHEAT barbecue to medium-low.
HEAT a large saucepan over medium. Add oil, then onion. Cook, stirring constantly,about1min. Add ketchup, chili sauce, sugar, hoisin, garlic powder, Worcestershire, chili flakes and salt. Continue to cook, stirring frequently to keep sauce from splattering, 5 to 8 min. Reserve 1/3 cup and scrape remaining sauce into a small bowl.
OIL grill. Barbecue chicken, with lid closed, for 15 min. Flip and brush with sauce from pan. Continue barbecuing, brushing with sauce and turning often, until springy when pressed, about 15 more min. Serve with reserved sauce.