Begin by combining the boneless, skinless chicken breasts in a bowl with soy sauce, cornstarch, rice wine vinegar, sesame oil, ground ginger, and white pepper. Cover and refrigerate for 30 minutes.

Bring a large pot of water to a rolling boil, add the lo mein noodles, and cook according to package directions (about 3-5 minutes). Drain and rinse under cold water, then toss with sesame oil.

In a medium bowl, whisk together soy sauce, oyster sauce, brown sugar, cornstarch, remaining sesame oil, rice wine vinegar, and chicken broth until smooth.

Heat a wok or large skillet over medium-high heat, add vegetable oil, and cook the marinated chicken for 5-7 minutes until browned and cooked through. Remove and set aside.

In the same wok, add minced garlic and ginger, stirring for 30 seconds, then add bell peppers, mushrooms, and carrots. Sauté for 3-4 minutes until tender-crisp.

Return the cooked chicken to the wok along with the prepared sauce. Stir to combine and cook for an additional 1-2 minutes.

Add the cooked lo mein noodles to the wok and toss everything together for 1-2 minutes until well mixed and heated through. Serve and garnish with green onions.