Heat the olive oil over medium heat in a large Dutch oven or stock pot. Add the onion, celery, bell pepper and garlic to the pot and cook, stirring often, until the vegetables have softened, about 5 minutes. Add the chicken stock and chicken to the pot along with the oregano, basil, salt and pepper. Spiralize the zucchini to make “zoodles” and add them to the pot (you can also buy pre-spiralized zoodles). Bring to a boil, then reduce to a simmer, simmering and stirring occasionally for 10 minutes or until the zoodles are al dente. Taste for seasoning, and add more salt and pepper if needed.