Preheat oven to 350F.
Add the oil to an extra-large pot.
Once the oil is hot, add the onions and stir until they are translucent.
Add the chicken and let it simmer for 5-7 minutes.
While it’s cooking, chop the mushrooms and peppers.
Add the salt, sugar, pepper, tomato juice, and red wine vinegar.
Crush the whole tomatoes by hand or by using a pastry cutter. This is better than buying “crushed tomatoes” as the flesh of the tomatoes really make the dish better!
Stir continuously to combine, then add the mushrooms and peppers.
Cover and let it simmer for about 20 minutes.
Transfer to a large baking dish and put it in the oven for 40 minutes.
Remove from the oven and serve with rice, mashed potatoes, pasta, or your choice of starch!