Put a large covered pan of salted water on to boil. Chop the chicken into bite-sized chunks and toss in a bowl with 1 tbsp cornflour to coat. Heat a wok or deep frying pan for 2 mins over a high heat. Add ½ tbsp oil and the chicken. Stir fry for 5 mins, turning once or twice, till the chicken is browned all over.
While the chicken fries, peel and finely slice the onion. Halve or quarter the shiitake mushrooms. Finely slice the cavolo nero.
Lift the chicken out of the pan and pop on a plate. Add the red onion, shiitake and cavolo nero to the wok with 2 tbsp water. Stir fry for 5 mins till the veg start to soften.
While the veg fry, peel and grate both garlic cloves and the ginger.
The pan of water should be boiling by now. Add 2 bundles of noodles and simmer for 4 mins.
Return the chicken to the wok. Add the grated garlic and ginger along with 1 tbsp tamari and the sweet chilli sauce. Pour in 100ml boiling water. Bubble for 5 mins, stirring occasionally, till the sauce has reduced a little.
The noodles should be cooked by now. Drain them in a colander, then tip into the wok and use 2 forks to pick up and drop the noodles, chicken and veg a few times to mix them together.
Divide the chicken noodles between 2 warm bowls and serve, adding a splash more tamari if you think it needs it.