Place both broths in a dutch oven or large soup pot. Bring to a boil and reduce heat.
Add chicken to the broth and poach uncovered for 25-30 minutes, until the internal temperature of the chicken reaches 170 degrees. Remove chicken from broth and set aside to cool slightly.
Add the carrots, celery, onion, onion soup mix, and remaining seasonings to the broth. Bring to a boil and reduce heat. Cover and simmer for 10-15 minutes until the vegetables are tender. If eating immediately, add the cheese tortellini during the last 5 minutes of cooking and cool until tender.
Dice the cooked chicken up and also add while the tortellini is cooking.
If freezing: Do not add the tortellini and allow the soup to cool. Dice up the cooked chicken and add to the cooled soup. Once the soup is completely cooled mix in the frozen tortellini and place in freezer containers. This can be frozen for up to 3 months.
To use the frozen soup: Thaw in the refrigerator overnight. Place in a pan and heat to boiling. Reduce heat and cook for 5-10 minutes or until tortellini is tender. Serves 6.