Cook the egg noodles according to package instructions. Drain in a colander in the sink and rinse under cold running water. Shake the colander to drain off excess water and pat the noodles dry with a towel.
In a medium bowl, combine 2 teaspoons soy sauce, rice wine or sherry and sesame oil. Mix well.
Slice the chicken into fine, 2-inch shreds. Add to soy sauce mixture. Set aside to marinate for about 10 minutes.
Heat 1/2 of the peanut oil in a wok or large frying pan over a high heat.
When oil is very hot, but not smoking, add the chicken mixture. Stir-fry for about 2 minutes. Transfer chicken to a plate, and keep warm.
Wipe the wok clean with a paper towel.
Add remaining peanut oil and heat.
Add bok choy, garlic, ginger, carrots, snow peas, bean sprouts, ham and mushrooms. Stir-fry for another minute or so.
Add in the noodles, oyster sauce, scallions and remaining soy sauce, to taste. Continue to stir-fry until the noodles are heated through.
Taste. Add salt and pepper, to taste.
Add chicken and any juices to the noodle mixture. Bring to a boil, and stir to coat the chow mein mixture.
Transfer mixture to a serving bowl or plate and sprinkle with chow mein noodles.
Serve hot.