Prepare the soy sauce mixture in a bowl by combining soy sauce, dark soy sauce, oyster sauce, rice vinegar, sesame oil, and brown sugar. Mix until the brown sugar dissolves.
Add corn starch and water. Mix until the corn starch is mainly incorporated into the mixture. Set the sauce aside.
Rinse the lettuce leaves. Shake as much water off of it and set it aside to dry.
Chop water chestnuts, mushrooms, green onions, and basil and set them aside. Chop onions and set them aside separately from the other ingredients.
Heat a large skillet or pan on medium-high heat. Coat it with desired cooking oil. Add onions and cook for 5 minutes or till semi-translucent.
Add ground chicken to the pan. Use a wooden spatula or a meat chopper to separate and crumble the meat. Once you crumble the meat to your liking, add the soy sauce mixture to the ground chicken. Mix until all the meat is coated with the sauce.
Add all other ingredients to the pan, water chestnuts, mushrooms, green onions, and basil. Mix until all ingredients are incorporated with the ground chicken. Let it simmer for about 5 mins.
Transfer to a serving plate and let it rest and cool for about 5 minutes before serving.
Top with garnishes or serve it on the side.
Serve with lettuce leaves.
Refer to the post above for substitutions, tips, and common questions on the recipe.