Place chicken between 2 sheets of heavy duty plastic wrap and flatten to
1/4" thickness, using meat mallet or rolling pin.
Brush half of soy sauce mixture over chicken, coating both sides.
Coat grill rack with cooking spray, place on grill over med-hot coals.
Place chicken on rack, grill, covered, 8 to 10 minutes or until chicken is
done, turning and basting frequently with remaining soy sauce mixture