MIX chili powder, garlic, cayenne pepper and 5 Tbsp. lime juice until well blended. Pour over chicken in large shallow dish; turn to coat both sides of each wing. Refrigerate 30 min. to marinate, turning chicken after 15 min.
HEAT oven to 400ºF. Remove wings from marinade; place in single layer on baking sheet sprayed with cooking spray. Discard marinade.
BAKE 35 to 40 min. or until wings are done, turning after 20 min. Brush with half the barbecue sauce mixture; bake 5 min., turning and brushing with remaining barbecue sauce mixture after 3 min.
MIX sour cream, onions, zest and remaining lime juice. Serve with wings.
serving size = 1 chicken wing (89 g) + 1-1/2 Tbsp. (22 mL) sauce