Heat olive oil in a large pot over medium heat.
Add sliced sausage and cook until browned, about 5-7 minutes.
Stir in diced onion, garlic, carrots, and celery; cook until vegetables are tender.
Add chicken broth and canned tomatoes to the pot.
Season with Italian seasoning, salt, and pepper.
Bring the mixture to a boil, then reduce heat and simmer for 10 minutes.
Add the tortellini to the pot and cook until tender, about 5-7 minutes.
Taste and adjust seasoning if necessary.
Remove from heat and let cool slightly.
Serve hot, garnished with fresh parsley.