In a large pot over medium heat, add the oil, sausage, and 3 of the onions for about 5-6 minutes until lightly browned.

Add the tomatoes, chicken broth, milk, and pasta. Stir together.

Bring this to a boil, turn down and let simmer for 15 minutes. Remove from heat and stir in cheese.

Serve with the extra green onion for a garnish.