Cook the noodles according to package instructions, drain, rinse briefly if needed, and set aside.
Heat the large frying pan or wok over medium-high heat and add the oil.
Working in small batches, add the chicken pieces to the hot pan and fry until golden and cooked through; remove to a plate and repeat until all chicken is cooked.
Add the broccoli, snow peas, green beans, red capsicum and baby corn to the pan and stir-fry until vegetables are bright and just beginning to soften but still slightly crisp, about 2–4 minutes.
Stir in the minced garlic, oyster sauce, soy sauce and brown sugar; mix to combine and coat the vegetables.
Add the cooked noodles and the cooked chicken back to the pan, toss gently, and cook for 2–3 minutes more until everything is heated through and well combined.
Serve immediately.