1. Cook noodles according to package directions, omitting salt and fat. Drain in a colander over a bowl, reserving 2 cups cooking liquid.
2. Heat stock and next 4 ingredients in a saucepan over medium-low heat.
3. Add cooking liquid and chicken to milk mixture; cook 3 minutes or until chicken is heated. Add noodles and cabbage; cook 2 minutes or until cabbage wilts. Sprinkle with cilantro and serrano; serve with Sriracha.