In a large pot, heat oil over medium heat. Add ground sausage and chopped onions. Break up the sausage as it cooks.
Halfway through cooking, add diced bell peppers and minced garlic to the pot. Continue cooking until the sausage is no longer pink.
Season the mixture with salt, pepper, garlic powder, Italian seasoning, smoked paprika, and red pepper flakes. Stir well to combine.
Pour in fire-roasted tomatoes, tomato sauce, and chicken broth. Stir to incorporate all ingredients.
Bring the soup to a simmer and cook for at least 30 minutes, or until the bell peppers are tender.
Taste the soup and adjust seasoning with additional salt, pepper, or garlic powder if needed.
Serve the soup hot, accompanied by cooked rice or pasta. Garnish with chopped green onions and serve with warm bread on the side.