WASH lettuce in cold water, gently pulling leaves apart. Gently spin dry in a salad spinner and sort through leaves reserving any larger leaves for another use and the small ones for filling. Refrigerate until ready to use. HEAT oil in a large skillet over medium-high. Add chicken and cook, breaking meat apart with the back of a wooden spoon, until nicely browned. Add garlic, ginger and mushrooms. Cook 2-3 minutes. Stir in water chestnuts, hoisin, soy sauce, chili garlic sauce, rice vinegar and sugar. Cook until all moisture has evaporated, about 2 minutes. Remove from heat and allow to cool completely. ARRANGE lettuce leaves on a serving platter. Divide chicken mixture between lettuce leaves and top with green onion, carrot, red pepper, nuts and crispy fried shallots.