Coat cold cooking grate with cooking spray, and place on grill. Preheat grill to 350° to 400° (medium-high).
Stir together brown sugar and next 6 ingredients in a small bowl until well blended. Place chicken in a shallow dish; add brown sugar mixture, and turn chicken to coat, pressing mixture into chicken.
Place chicken on cooking grate, and grill, covered with grill lid, over 350° to 400° (medium-high) heat 5 to 6 minutes on each side or until done. (Meat thermometer should read 165° when inserted into thickest portion of breast.)
Place chicken on a serving platter. Spoon Confetti Corn Relish over top of and around chicken. Garnish, if desired.