Heat gas or charcoal grill. Cut 20x18-inch sheet of heavy-duty foil; spray with cooking spray. Place ham on center of sheet. Top with potatoes, pasta sauce and cheese.
Bring up 2 sides of foil over ham mixture so edges meet. Seal edges, making tight 1/2-inch fold; fold again, allowing space for heat circulation and expansion. Fold other sides to seal.
Place packet on grill over low heat. Cover grill; cook 20 to 25 minutes, rotating packet 1/2 turn after 10 minutes, until potatoes are tender.
To serve, cut large X across top of packet; carefully fold back foil to allow steam to escape. Sprinkle with chives.