To marinate the chicken, in a bowl, add the chicken and sprinkle with salt. Mix until the chicken absorbs the salt and becomes slightly tacky. Add the white pepper, soy sauce, and dark soy sauce and mix well. In a small bowl, combine the cornstarch and water to form a slurry, then mix it into the chicken. Add the cooking oil and mix again to seal in moisture. Let the chicken marinate while preparing the other ingredients.
To prepare the vegetables and sauce, slice the onion, shred the carrot, slice the cabbage, cut the scallions, and mince the garlic. In a bowl, whisk together the soy sauce, dark soy sauce, sake, mirin, brown sugar, and chicken stock until combined.
To cook the noodles, in a pot over high heat, bring water to a boil. Add the lo mein noodles and cook for about 3 minutes until just al dente. Transfer to cold water to stop the cooking, then drain well.
To stir-fry the chicken, in a wok over high heat, add 1 tablespoon of cooking oil. Add the marinated chicken and stir-fry for about 3 minutes until fully cooked. Add the garlic and stir-fry for about 10 seconds until fragrant. Remove and set aside.
To stir-fry the vegetables, in the same wok over high heat, add 1 tablespoon of cooking oil. Add the onion, carrot, and cabbage and stir-fry for about 1 minute until slightly softened. Remove and set aside.
To make the teriyaki chicken lo mein, in the wok over high heat, add the remaining tablespoon of cooking oil. Add the noodles and stir-fry until heated through. Return the chicken and vegetables to the wok and pour in the teriyaki sauce. Stir-fry for about 1 minute, allowing the noodles to absorb the sauce. Lastly, add the scallions and give everything a final toss before serving immediately.
