In a large bowl, combine the first 12 ingredients. Add turkey; mix lightly but thoroughly.
Place 1 tablespoon filling in center of each pot sticker wrapper. (Cover remaining wrappers with a damp paper towel until ready to use.) Moisten wrapper edge with water. Fold wrapper over filling; seal edges, pleating the front side several times to form a pleated pouch. Stand dumplings on a work surface to flatten bottoms; curve slightly to form crescent shapes, if desired.
Place trivet insert and 1 cup water in a 6-qt. electric pressure cooker. Line trivet with 3 cabbage leaves. Arrange 10 dumplings over cabbage (do not overlap). Lock lid; close pressure-release valve. Adjust to pressure-cook on high for 7 minutes. Press cancel. A thermometer inserted in dumpling should read at least 165°.
Transfer dumplings to a serving plate; keep warm. Discard cabbage and cooking juices. Repeat with additional water, remaining cabbage and dumplings. If desired, serve with chili sauce.Freeze option: Cover and freeze cooled dumplings on parchment-lined baking sheets until firm. Transfer to a large freezer container. To use, microwave dumplings, covered, for 30-45 seconds or until heated through.