Asian Chicken Lettuce Wraps

Some of my favorite foods to make are copycat recipes- dishes that exact replicas or the original recipes themselves from restaurants. I had wanted to make this one in particular for a while, but finally now got to it. This recipe is based on a copycat recipe based on P.F. Chang's Chicken Lettuce Wraps. I didn't follow the directions even though it was rated so highly because well... they don't make sense (why none of the commenters mention this, I don't know...) and I had a few more veggies I wanted to sneak into them. So I (mostly) created the "special sauce" listed in the recipe then loosely followed the rest. Here below is my recreation of that recipe.

1 chicken breast, chopped into tiny pieces
1/2 small zucchini, shredded
1/2 red pepper, finely chopped
1/2 yellow onion, finely chopped
1 can water chestnuts, drained and finely chopped
1 can mushrooms, drained and finely chopped
4-5 giant iceberg lettuce leaves

Special Sauce
1/4 cup teriyaki sauce
1/4 cup water
1/4 cup sugar
2 tablespoons white wine vinegar
2 tablespoons ketchup
1 tablespoon lemon juice
1/8 teaspoon olive oil
1 teaspoon minced garlic

Saute chicken until no longer pink, add veggies and special sauce. Cook for several minutes, until sauce thickens. Spoon into lettuce cups.