In a bowl, mix soy sauce, oyster sauce, sesame oil, and brown sugar. Keep the mix aside.
Heat vegetable oil in a large wok or skillet. Add onion, garlic, ginger, and the white part of spring onion. Saute until the onion turns translucent.
Add mushrooms and saute until the moisture released by them dries up.
Next, add sliced carrot, bell pepper, broccoli florets, and chopped chilies. Saute on high heat for around 2-3 minutes.
Add the sauce mix and saute for about a minute.
With the help of your spatula, push the vegetables towards the corner of the wok to create some space at the center.
Pour vegetable stock at the center and let it simmer.
Put Instant noodles on top of the vegetable stock and let them remain like that for around 2 minutes. Once the noodle strands start becoming soft, flip the ramen bricks over. Let the other side also get cooked for about 1-2 minutes. You can cover the pan to fasten the process.
Add chopped spring onion greens and mix everything with a pair of tongs. Cook for another 2 minutes and then switch off the stove. Enjoy hot!