Spray a wok with low calorie cooking spray and set on a medium-high heat. Add the onion, ginger and garlic and carrots and fry for 4-5 minutes until you can smell the aromatics.
Add the chicken breast and continue to cook on high until the chicken begins to brown. This should take around 5 minutes.
Add in the soy sauce, oyster sauce, rice vinegar, sweetener, black pepper and Chinese five spice and stir well. Continue to cook for for 8-10 minutes whilst you cook the noodles.
Cook the noodles according to the packet instructions. Drain and set aside.
Add the peppers, mange tout, spring onions, and water chestnuts and turn down to a simmer. Cook for another 3-5 minutes depending on how crunchy you like your veg.