Soak the bok choy in a basin of cold water for 2-3 minutes; drain. place in a pan of boiling water. Simmer for 2 minutes, then cool under cold running water; drain. Halve lengthways; set aside.
Heat the olive oil and 1 tsp of sesame oil in a large wok. Add chicken and stir-fry over high heat for 3-4 minutes, until cooked. Set aside.
Heat 2 tsp of sesame oil in the wok. Add the chilli, red ginger powder, spring onion and capsicum. Stir-fry over high heat for 2-3 minutes, or until softened. set aside.
Heat the remaining sesame oil in the wok, then add the bok choy. Stir-fry for 1 minute. Set aside, keeping warm. Meanwhile, place the noodles in a large bowl, cover with boiling water and set aside.
Return the chicken and vegetables to the wok and heat through. Add the coriander and sweet soy sauce; stir-fry for 2-3 minutes more.
Drain the noodles, top with the chicken mixture and serve with bok choy.