In a bowl, mix all marinade ingredients with the chicken until well coated. Set aside while you prepare the other components.
Boil the chow mein noodles according to package instructions. Drain and rinse under cold water to stop the cooking. Set aside.
Heat 1 tablespoon oil in a pan over medium-low heat. Cook the chicken for 3-4 minutes per side, or until the internal temperature reaches 165°F (74°C). Remove and let rest.
In the same wok or pan, increase heat to medium-high and add 1 tablespoon oil. Add mushrooms and garlic and cook for 2minutes.
Add sliced peppers and cook for another 2 minutes, stirring occasionally.
Add the coleslaw and cook for a further 2 minutes until just tender but still crisp. Remove onto a plate.
In the same wok, heat the remaining 1 tablespoon oil. Add the noodles and leave undisturbed for 1 minute to lightly crisp. Stir and repeat this process 2–3 times.
Return the vegetables to the wok. Add the prepared sauce and toss everything together, stirring and sizzling for about 1minute until well coated and heated through.
To serve, slice the chicken and arrange over the chow mein. Serve hot, garnished generously with spring onions.