Prepare ingredients: slice the chicken sausage into rounds (or remove from casings), chop the onion, mince the garlic, cut broccoli into small florets, and chop the red bell pepper.
Heat the olive oil in a large soup pot over medium-high heat.
Add the chicken sausage and sauté for about 5 minutes, until browned.
Add the chopped onion and cook for about 4 minutes, until softened.
Stir in the minced garlic and the orzo and cook for about 30 seconds, stirring constantly.
Add the Italian seasoning, chicken broth, and tomato sauce, stirring to combine.
Bring the mixture to a gentle boil, then add the broccoli florets and chopped red bell pepper.
Reduce heat to medium or medium-low so the mixture gently bubbles. Cook uncovered, stirring fairly often, for about 10 minutes or until the orzo is tender and the liquid is mostly absorbed.
Season to taste with salt and pepper, and serve immediately with freshly grated parmesan if desired.