This is a poor comparison. Over the last decade it is unlikely that the techniques and training to become a doctor have changed substantially. Sure, there are medical advances and new technologies that change how a doctor does business, but fundamentally the pace of change is slow. On the flip side, AI and ML have made significant strides within the last decade. Unless your career required you to keep up with and innovate in the space, you probably are well behind the times. A nanodegree may not stand well on its own, but coupled with previous experience it may be a way to show you are actually familiar with up to date trends and techniques on the topic.