Sprinkle chicken with salt and pepper. Let stand, covered, for 30 minutes.
Coat a cold cooking grate of grill with cooking spray, and place on grill. Preheat grill to 350 - 400°. Grill chicken, covered with lid, 5 to 10 minutes on each side or until browned. Reduce grill temperature to 250° to 300°; grill chicken, covered with lid, for 20 to 30 minutes. If using a charcoal grill, place charcoal to one side. Use the hot side for the first part of grilling and the empty side for the second part of grilling.
Meanwhile, prepare Spicy Honey-Lime Barbecue Sauce. Reserve 1 cup of the sauce.
Brush the chicken with the remaining barbecue sauce. Cover with grill lid and grill 10 more minutes or until done. Serve chicken with reserved barbecue sauce. Garnish, if desired.
For the sauce: Melt the butter in a small saucepan over medium heat; add onion, and saute 4 to 5 minutes or until tender. Stir in chili sauce, next 3 ingredients, and 1/3 cup water; bring to a boil. Reduce heat to low, and simmer 5 minutes. You can store this in the refrigerator for up to 1 week.