Prepare the Sauce: In a medium bowl, whisk together ¼ cup soy sauce, 2 tablespoons oyster sauce, 2 tablespoons hoisin sauce, 1 teaspoon sesame oil, and 1 tablespoon brown sugar until smooth.

Cook the Chicken: Heat 1 tablespoon of vegetable oil in a large skillet over medium-high heat. Add 1 pound of ground chicken and cook for about 4-5 minutes until brown.

Add Aromatics: Push the chicken to one side and add ½ cup diced onion. Sauté for about 2 minutes then stir in 2 teaspoons minced garlic and 1 teaspoon minced ginger. Cook for another minute.

Incorporate Crunch: Add ½ cup diced water chestnuts to the skillet, stirring to combine and warm through for about 2 minutes.

Mix in the Sauce: Pour the prepared sauce over the chicken mixture, stirring well and cook for another 1-2 minutes until slightly thickened. Add 1 tablespoon rice wine vinegar and half of the sliced green onions.

Serve: Transfer the chicken filling to a serving bowl, garnish with green onions and sesame seeds. Serve with lettuce leaves and lime wedges on the side.