Finely dice onion and medium dice carrots, celery, zucchini and chicken breast.
In a large soup pot, heat up 1 tbsp olive oil over medium heat. Add onion, carrot and celery, and saute until fragrant.
Add the rest of the ingredients except for chicken, and bring mixture to a boil. Cover and let simmer for 30 minutes. Stir occasionally.
This is an optional step if you want a thicker soup. Using an immersion blender, blend up a little bit of the vegetables in the pot to give your soup a heartier texture. If you don't have an immersion blender, you can just scoop out about 1 cup of the vegetables and transfer to a blender to blend until smooth, then transfer back to the pot.
After 30 minutes, add chicken and let simmer for 10 more minutes.
Taste and season with more salt and pepper if needed. Enjoy!