In a large pot, heat a tablespoon of olive oil over medium heat.
Add diced onions, carrots, and celery; sauté until softened, about 5 minutes.
Stir in minced garlic and cook for an additional minute.
Pour in the chicken broth and bring to a boil.
Add the shredded chicken, diced tomatoes, and Italian seasoning.
Season with salt and pepper to taste.
Reduce heat and let simmer for 10 minutes.
Add tortellini and cook according to package instructions, about 5-7 minutes.
Taste and adjust seasoning if necessary.
Serve hot, garnished with fresh parsley.