Heat a large pot over medium heat. Add olive oil, onion, garlic, chicken, and celery to the pot. Sauté them until the onions become translucent, about 2 to 3 minutes.
Add the carrots, butternut squash, cabbage, can of tomatoes, vegetable stock, thyme, salt, and pepper to the pot. Stir everything together, cover the pot, and bring it to a boil.