1 (8-ounce) can whole water chestnuts, drained and diced (optional)
2 green onions, thinly sliced
Kosher salt and freshly ground black pepper, to taste
1 head butter lettuce
1/4 cup chopped peanuts, optional
In a small bowl, whisk together soy sauce, dry sherry, chili garlic sauce, brown sugar, rice vinegar, cornstarch, sesame oil and 1/4 cup water; set aside.
Heat olive oil in a saucepan over medium high heat. Add ground chicken and cook until browned, about 3-5 minutes, making sure to crumble the chicken as it cooks; drain excess fat.
Stir in garlic and zucchini until softened, about 1-2 minutes. Stir in the soy sauce mixture until slightly thickened, about 1 minute. Stir in chestnuts and green onions until tender, about 1-2 minutes; season with salt and pepper, to taste.
To serve, spoon several tablespoons of the chicken mixture into the center of a lettuce leaf, taco-style, garnished with peanuts, if desired.