Coat a nonstick skillet with oil spray. Add the mushrooms, peppers, and bok choy.
Sauté for two minutes. Add the broccoli slaw.
Slowly, add as much chicken broth as needed to keep from burning. Then add the ginger, water chestnuts, and scallions, and continue to sauté until vegetables are soft, but still somewhat crunchy.
In a small bowl, mix the wasabi mustard, soy sauce, and chicken broth to form a sauce. Pour into a pan, and keep on low heat for about a minute.