Arrange lettuce leaves on a large platter. Pour chili sauce into a small bowl; place on platter with leaves. Mix chicken, scallions, soy sauce, and cornstarch in a medium bowl; marinate 10 minutes at room temperature, stirring occasionally. Heat oil in a large nonstick skillet. Add mushrooms; stir-fry 15 seconds. Add garlic and ginger and stir-fry 10 seconds. Add chicken mixture and cook, stirring often, until golden brown and cooked through, about 3-4 minutes. Spoon chicken mixture into lettuce leaves, dividing equally. Garnish with cashews. Roll leaves around filling and dip into chili sauce.
Per serving: 168 calories, 10 grams fat, 9 grams Carbohydrate Nutritional analysis provided by Bon Appétit