To prepare the chicken, slice the chicken breast against the grain into ¼-inch slices. In a bowl, add the sliced chicken and sprinkle with salt, mixing until 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 to seal in moisture and prevent sticking. Let marinate while preparing the remaining ingredients.
To prepare the vegetables, cut the Chinese broccoli into bite-sized pieces and mince the garlic.
To make the sauce, in a bowl, whisk together the soy sauce, dark soy sauce, oyster sauce, fish sauce, sugar, and water until combined.
To cook the noodles, in a pot over high heat, bring water to a boil. Add the dried rice noodles and cook for about 3 minutes until softened but still slightly undercooked. Transfer immediately 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. Remove and set aside.
To stir-fry the eggs and Chinese broccoli, in the same wok over high heat, add 1 tablespoon of cooking oil. Crack in the eggs and stir-fry until partially set, then push to one side. Add the Chinese broccoli and garlic and stir-fry for about 1 minute until fragrant. Remove everything and set aside.
To stir-fry the noodles and combine, in the wok over high heat, add the remaining tablespoon of cooking oil. Add the drained noodles and stir-fry until heated through. Return the chicken, eggs, and Chinese broccoli to the wok and pour in the sauce. Toss for about 1 minute until evenly coated. Let the noodles sit undisturbed for about 15 seconds to develop a light char before serving.
