In Round or Multipurpose Steamer, combine rice noodles and boiling water. Ensure noodles are completely submerged—add more boiling water as needed. Stir occasionally until tender, about 8–10 min. Drain and rinse under cold water.
Meanwhile, in a small bowl, whisk together seasoning, vinegar, soy sauce, and water. Set aside.
Heat oil in Wok over medium-high heat. Add chicken. Stir-fry until cooked, breaking up chunks as needed, 5–6 min.
Thinly slice pepper; add to wok along with snap peas. Stir-fry 1–2 min or until tender crisp. Add noodles and sauce. Carefully mix everything using a scooping motion, 1 min. The wok will be full! Serve immediately and add toppings, if desired.