In a large pot, heat olive oil over medium heat. Add the onion and garlic and sauté until the onion is translucent.
Add the chicken cubes and cook until browned on all sides.
Add carrots, celery, and zucchini to the pot. Cook for about 5 minutes, stirring occasionally.
Pour in the chicken broth and add the thyme, oregano, salt, and pepper. Bring to a boil.
Reduce the heat and let it simmer for about 20 minutes, until the vegetables are tender.
Add the peas and spinach, and let it cook for another 5 minutes.
Adjust seasoning if needed and serve hot.