In a large saucepan, bring broth and water to boil. Add carrots, reduce heat and simmer until tender, 10 to 12 minutes.
Add tortellini and simmer until tender, 2 to 4 minutes. Add shredded chicken and cook, stirring occasionally, until heated through, 1 to 2 minutes more.
Season soup with salt and pepper, to taste. Sprinkle with parsley. Top with shaved Parmesan cheese, if desired.