In a large pot or Dutch oven over medium heat, cook the Italian sausage, breaking it apart as it cooks with a fork. Once browned and cooked through, remove it from the pot and set it aside.
In the same pot, add the diced onion and minced garlic. Sauté for a few minutes until the onions are translucent.
Add the diced bell peppers and cook for another 3-4 minutes until they begin to soften.
Pour in the chicken broth and diced tomatoes with their juices. Add the dried basil, dried oregano, salt, and pepper. Stir well and bring the mixture to a boil.
Reduce the heat to low and let the soup simmer for about 15-20 minutes.
Adjust seasoning as needed and optionally add red pepper flakes.