Place the chicken and marinade ingredients in a bowl. Mix so that the chicken is fully coated and set aside for a few minutes (if you had more time you could place in the fridge for a little while but it'll still taste great if you use straight away).
Cook the noodles according to package instruction. Heat a large wok or frying pan over a high heat then place the chicken into the wok and stir fry until browned on either sides, about 5 minutes per side. Set aside.
Turn the heat down then add the coconut milk, sweet chilli sauce, rice vinegar, sugar and garlic and cook until it's thickened a bit. Add the noodles, pak choy and some of the coriander. Chop the chicken and add to the skillet along with the sesame oil. Give everything a good mix then serve topped with chopped peanuts, more coriander and some wedges of lime.