HEAT grill to medium-high heat.
MAKE deep lengthwise cut along inside curve of each banana, being careful to not cut through to opposite side. Place bananas on centers of 4 large sheets heavy-duty foil.
OPEN bananas gently; spread with peanut butter. Top with remaining ingredients. Fold foil to make 4 packets.
GRILL, filled sides up, 8 to 10 min. or until heated through. Cut slits in foil to release steam before opening packets.