In a large pot, sauté onion in olive oil until softened.
Add chicken broth, carrots, and celery. Bring to a boil, then reduce heat and simmer for 10 minutes.
Stir in shredded chicken and thyme. Simmer for 5 more minutes.
Season with salt and pepper to taste.
Notes
This soup can be easily customized to your liking. Add other vegetables, such as potatoes or peas. You can also use different types of broth, such as vegetable broth.