There are lots of chow mein recipes out there, but this is how I like to make it. It reminds me of fast food chow mein, but it's not nearly as greasy. I call for chicken here, but use whatever protein you like- or none at all!
Marinate the chicken: Combine the 2 teaspoons soy sauce, rice vinegar, and sesame oil in a small bowl. Add the sliced chicken, and toss to completely coat. Set aside while you cook the noodles.
Cook the chow mein noodles according to package directions, drain well, and set aside.
Heat half of the oil (1 tablespoon) in a very large skillet or wok. When is is very hot, but not smoking, add the chicken mixture, and stir fry until the chicken is cooked through. Remove the chicken to a plate, set aside and keep warm.
Add the rest of the oil to the skillet, then add the cabbage, bok choy, water chestnuts and garlic; stir fry for a couple of minutes until the vegetables begin to wilt. Add the noodles, and continue to cook until the noodles are hot, and well combined with the vegetables.
Add the soy sauce and oyster sauce, toss to combine. Add the chicken, toss to combine.
Transfer the chow mein to a serving platter, and top with the chopped green onions. Serve immediately.