How to Make It
To prepare sauce, combine first 6 ingredients in a small saucepan; bring to a boil over medium heat. Reduce heat; simmer 15 to 20 minutes or until thickened.
To prepare chicken, combine garlic powder, chili powder, paprika, cumin, salt, and black pepper in a small bowl. Loosen skin from breast halves by inserting fingers, gently pushing between skin and meat. Rub the spice mixture evenly under loosened skin; let stand at room temperature 30 minutes.
Preheat grill to medium-high heat, lighting only one side of the grill to enable both direct and indirect grilling.
Coat grill rack with cooking spray; place chicken, skin side down, on lit side of grill (direct heat). Cover and grill 8 minutes on each side. Remove skin from chicken; discard skin. Baste chicken with sauce mixture. Move chicken to the unlit side of the grill (indirect heat). Cover and grill an additional 5 minutes on each side or until done, basting every minute. Serve with remaining sauce.