Wash iceberg lettuce leaves and let drip dry until you are ready to serve.
Remove and discard stems from shiitake mushrooms. Then chop the mushroom caps. Chop napa cabbage keeping the leaves and stems separate.
Lightly coat a wok or skillet with cooking spray and place over medium-high heat. Add turkey and then stir-fry until no longer pink, about 3 to 4 minutes. Remove turkey from the wok and set aside.
Lightly recoat the wok or skillet with cooking spray. Add chopped cabbage stems and onion; stir-fry until tender, about 2 minutes.
Stir in hoisin sauce, soy sauce and five-spice powder. Add cabbage leaves, mushrooms and water chestnuts; stir-fry for about 1 minute. Add cooked turkey back into the skillet and stir-fry until well combined and heated through, about 2 more minuets.