Place chicken in a greased 3-qt. slow cooker; sprinkle with garlic, salt and pepper. Top with cream cheese. Cook, covered, on low until a thermometer inserted in chicken reads 165°, 2-1/2-3 hours. Remove chicken; shred with 2 forks. Return to slow cooker.
Stir in Swiss cheese and ham. Cover and let stand 15 minutes until cheese is melted. Stir before serving on rolls. Sprinkle with green onion.