In the same pot, add the onion, celery and garlic. Sauté for 2-3 minutes, or until the onion is translucent and fragrant. Add the cut pork chops, butternut squash, thyme and bay leaf, and sauté for another minute. Season with pepper. Add chicken stock, tomatoes and beans; mix until everything is well combined. Reduce heat, cover with lid and let cook for 15-20 minutes, or until the butternut squash is soft. Add kale, cover and cook for 5 more minutes.