Put the chicken in a mixing bowl. Add the remaining chicken ingredients and mix well.
Heat a wok over a high heat, until smoking. Pour in half the oil. Add the chicken and stir-fry for 6-8 minutes, until cooked through and covered in the sauce. Transfer to a bowl and wipe the wok clean so it does not burn.
Reheat the wok over a high heat. Add the remaining oil, the mushrooms, the pak choi, and half the spring onionsand chilli. Mix well. Stir-fry for 4-6 minutes until the mushrooms are tender.
Return the chicken to the wok and add the noodles, dark soy and light soy sauce. Continue to stir-fry for 1-2 minutes, until the chicken is piping hot. Serve immediately with the remaining spring onions and chilli scattered over