If chicken wings are whole, cut wings into 3 sections; discard the wing tip section.
Combine maple syrup, chili sauce, onion, mustard, Worcestershire sauce and red pepper flakes in a large mixing bowl.
Stir or whisk ingredients to combine.
Remove one cup sauce for basting and refrigerate.
Add chicken wings to sauce and stir to combine.
Transfer mixture to a zip lock bag.
Seal bag; turn to coat; refrigerate chicken wings for 4 hours, turning occasionally.
Drain and discard marinade from wings.
Grill chicken, covered, over medium heat for 12-16 minutes, turning occasionally.
Brush with reserved marinade.
Grill, uncovered, for an additional 8-10 minutes or until juices run clear.
Baste the chicken wings and turn wings over several times while grilling.
Transfer cooked chicken wings to a serving platter.
Serve wings with your favorite dipping sauce: honey mustard, chipotle or your favorite dipping sauce.