Heat the oil in a large wok, and add the onion, garlic and chilli. Cook over a medium heat for a couple of minutes, then add the remaining vegetables. Cook for 5 more minutes, stirring regularly.
While the vegetables are stir frying, boil the noodles if required, and drain.
Add the noodles to the vegetables, and then add all the ingredients for the dressing (agave nectar to brown sugar). I just add each ingredient straight to the pan, but you could mix the dressing up separately first if you prefer, and then add it all together.
Cook for a couple of minutes more, and then serve.