In a medium bowl, combine the thinly sliced chicken with 1 tablespoon of soy sauce, 1 teaspoon of cornstarch, and 1 teaspoon of sesame oil. Mix well until the chicken is evenly coated. Let it marinate for 5–10 minutes.

Bring a large pot of salted water to a boil. Add the lo mein noodles and cook according to package instructions, usually around 6-8 minutes. Drain and toss with sesame oil to prevent sticking.

In a small bowl, whisk together the remaining 3 tablespoons of soy sauce, oyster sauce, hoisin sauce, brown sugar, and chicken broth or water until the brown sugar is dissolved.

Heat 2 tablespoons of vegetable oil in a wok over medium-high heat. Add the marinated chicken and cook for 4-5 minutes until golden brown. Remove from pan.

In the same pan, add minced garlic and grated ginger, cooking for about 30 seconds until fragrant. Add bell peppers, shredded carrots, and snap peas. Stir-fry for 3–4 minutes.

Return the cooked chicken to the pan and pour in the prepared sauce. Let it simmer for 1–2 minutes.

Add the cooked noodles and sliced green onions, tossing gently together. Stir-fry for 1-2 minutes until heated through.