In a large bowl mix together the soy sauce, sesame oil, sherry, and cornstarch until well combined.
Cut the chicken thighs into large bite-size chunks. Place the chicken in the bowl with the marinade and stir to coat the chicken evenly in the marinade then set aside.
Heat the 3 TBSP of oil in a large wok over medium heat.
Add the ginger, garlic, star anise, sichuan peppercorns, and crushed red pepper to the pan and stir-fry just until fragrant, about 1 minute.
Add the chicken to the pan then increase the heat to high and stir-fry for about 3 minutes.
Stir in the potatoes, water, soy sauce, and sherry and bring to a boil.
Place a lid on the wok then reduce the heat to medium and cook while covered for about 10 minutes.
While the chicken cooks, cook the noodles according to package directions then drain and set aside.
Take the lid off the wok and continue to cook, uncovered, until the chicken is cooked through and the potatoes are tender, about 5 minutes.
Stir in the bell peppers and cook for about 2 more minutes then season with salt & pepper to taste.
Lay the cooked noodles on a large serving plate. Cover the noodles with the chicken and vegetables then top with sliced green onion.
