Slice chicken into 1/4-inch strips and marinate with salt, white pepper, soy sauce, Shaoxing wine, cornstarch, and avocado oil for 15–20 minutes.
Chop vegetables, mince garlic and ginger, and separate scallion whites from greens.
Mix stir-fry sauce with soy sauce, oyster sauce, dark soy sauce, Shaoxing wine, sesame oil, white pepper, sugar, water, cornstarch, and MSG if using.
Cook lo mein noodles 2 minutes less than package directions, drain, rinse with cold water, and coat with sesame oil.
Heat 3 tbsp avocado oil in a wok over high heat and sear chicken for 2–3 minutes until cooked through, then set aside.
In the same pan, sauté garlic and ginger for 15 seconds.
Add scallion whites, carrots, onions, and cabbage, cooking for 3–4 minutes until slightly wilted.
Return noodles and chicken to the pan, then pour in stir-fry sauce.
Toss everything together and cook for 1–2 minutes until the sauce thickens and evenly coats ingredients.
Add scallion greens, toss, and serve hot.