Mix chicken with egg white, 2 teaspoons cornstarch, and sesame oil in a bowl.
Bring a large pot of water to a boil. Add egg noodles; cook until soft, about 4 minutes. Drain. Spread out on paper towels to remove excess moisture.
Heat vegetable oil in a wok over medium heat. Cook and stir noodles in the hot oil until golden brown, 3 to 5 minutes per side. Drain on paper towels.
Stir chicken into the wok; cook, stirring frequently, until white, about 2 minutes. Transfer to a bowl using a slotted spoon.
Pour chicken stock into the wok; stir in spring onions, soy sauce, rice wine, white pepper, and black pepper.
Mix 1 tablespoon cornstarch and water together in a small bowl until smooth. Pour into the wok. Stir in oyster sauce. Add chicken and bean sprouts; cook and stir until chicken is tender and sauce is thickened, about 5 minutes. Serve over noodles.