In a large frying pan or wok, heat the oil, then add the chicken, and season with salt and pepper. Cook the chicken until it starts to brown, and the juices are running clear.
At this time if there is a lot of moisture in the pan, you can drain most of it off.
Add the garlic and ginger and cook for about 1 minute.
Add the onion and bell peppers, cooking for about 3 minutes. You don’t want to overcook the veggies so I would cook them maximum 3 minutes.
In a small bowl, mix together the sweet chili sauce and the vinegar. Then add it to the pan and cook over medium-high heat for a few more minutes, just until the sauce is reduced and the veggies are tender but crisp.
When you are ready to serve, sprinkle on the sliced green onion.