Place potatoes, carrots, celery, onions and broth in a large stockpot. Bring to a boil. Reduce heat, cover, and simmer 30 minutes. (Meanwhile, if desired, add chicken to a separate pot of boiling water.)
When potatoes are tender, add zucchini, cilantro, parsley and tomatoes. Simmer 15 minutes more. (Meanwhile, if desired, boil noodles as directed on package. If including, remove chicken from boiling water and shred; set aside.) When noodles are done, drain and set aside.
For veggie soup, serve warm in a bowl.
For chicken/turkey noodle soup, add desired portions of noodles and chicken to a bowl. Top with soup.