"From my experience many of the recipes I have found for chow mein and lo mein seem to be either dry or very bland. I have been working at this one and my family has decided that this is the one and I will never have to order out again."
Bring water to a boil in a large pot. Cook chow mein noodles until soft, 5 to 6 minutes. Drain and rinse with cool water.
Mix flank steak, teriyaki sauce, 2 tablespoons soy sauce, cornstarch, and 2 cloves garlic together in a small bowl.
Mix remaining 2 tablespoons soy sauce, 4 cloves garlic, 1 cup water, chow mein sauce mix, teriyaki glaze, and sriracha sauce in a separate bowl to make sauce.
Preheat a wok over medium-high heat; add 2 tablespoons peanut oil. Add steak and onion; cook and stir until beef is brown and onion is translucent, about 3 minutes. Transfer to a plate.
Pour remaining 2 tablespoons peanut oil into the wok. Add carrots, mushrooms, broccoli, and celery; cook and stir until browned, about 3 minutes.
Return steak and onion mixture to the wok. Add noodles, sauce, bean sprouts, shrimp, bok choy; cook, stirring occasionally, until noodles are heated through and shrimp are opaque, about 4 minutes. Season with pepper.