Add the celery, carrots, garlic, and Italian seasoning to the pot. Give it a good stir and continue cooking for a few more minutes.
Add the chicken broth to the pot. Increase the heat to high, and once it starts to boil, reduce the heat to a rapid simmer and let it cook for 10 minutes or until the veggies have softened to your liking.
Add the chicken and tortellini to the pot. Increase the heat to medium-high and let the soup cook for a few more minutes until the tortellini is cooked. If it starts to boil furiously, you may need to turn the heat down again.
Season with salt & pepper as needed and garnish with the chopped parsley. Serve immediately.
Notes
For an extra boost of flavor, use homemade chicken broth instead of store-bought.