In a large bowl, combine the first seven ingredients. Add chicken; mix lightly but thoroughly (mixture will be soft). With wet hands, shape mixture into 24 balls (about 1-1/4-in.). Select saute or browning setting on a 6-qt. electric pressure cooker. Adjust for medium heat; add oil. When oil is hot, brown meatballs in batches; remove and keep warm. Add water to pressure cooker. Cook 1 minute, stirring to loosen browned bits from pan. Press cancel.
Place trivet insert in pressure cooker. Place meatballs on trivet, overlapping if needed. Lock lid; close pressure-release valve. Adjust to pressure-cook on high for 7 minutes. Quick-release pressure.
In a small bowl, mix sauce ingredients. To serve, place 2 teaspoons sauce and one meatball in each lettuce leaf; top with remaining ingredients. If desired, serve with additional minced fresh cilantro.