pesto: In a food processor, combine basil, almonds, garlic, olive oil, parmesan cheese, and salt/pepper.
Mix the pesto with greek yogurt. Dice or shred the chicken and combine with pesto/yogurt mixture, oregano & onion. Spoon onto sandwich rolls and top with tomato and mozzarella. Put under broiler just long enough to melt the cheese -- 3minutes. Enjoy.