SAUCE: In a small bowl, whisk together all ingredients, set aside.
FILLING: Finely chop the chicken and mince the vegetables.
In a large fry pan, over medium-high heat, stir-fry the chicken in a little oil. When the chicken is longer pink, add in the rest of the filling ingredients and the sauce. Cook for 3 to 5 more minutes.
Spoon 1 to 2 tablespoons of the cooked filling mixture into each lettuce leaf. Top with more hoisin sauce, if desired. Eat taco style, wrapped neatly like a burrito.
Cook's Note: If you use chicken breast or tenderloin instead of thighs, you can save a lot of time reducing your food preparation. Thigh meat will require more effort, but taste better. While the chicken breast will be faster and healthier, but not quite as tasty.