1. In a large pot over medium heat add oil, onion and garlic. Sauté for 5 minutes, until soft then add all remaining ingredients except pasta. Bring to a simmer and cook for 20 minutes. Remove chicken and set aside.
2. Add Diamond seashell pasta to the soup pot and cook for 5-10 minutes, or until tender, stirring often so it doesn't stick.
3. Using two forks, shred the chicken then return it to the soup.
4. Season soup with salt and black pepper.
5. Serve hot topped with parmesan cheese.