In a large cast iron pot over medium heat, sear the Italian sausage on both sides in the olive oil. Remove from pot and set aside on a plate.
Add the zucchini, peppers, onions, thyme and oregano to the pot (add more olive oil if needed) and season with salt and pepper. Sweat, stirring occassionally. If the pan starts getting too dry and the fond begins to burn, add a little of the chicken stock at this stage to break it up.
Once the vegetables have started to soften, add all the remaining ingredients. Slice the sausage into 1/2in slices and add to the pan, along with any juices that may have escaped. Stir, cover, and simmer on medium low for 30 minutes, stirring occasionally.
Remove the lid and simmer, stirring occasionally, another 15 minutes or until the sauce has thickened. Serve over top noodles or riced vegetables.