I would guess CS193P is probably more in depth just in their lecture content alone than the Nanodegree lecture content.

And I can't speak to every Nanodegree, but the projects I worked on in my Nanodegree were 'easy' enough that it wasn't hard for the reviewers to mark. There wasn't a ton of room for creativity. Most importantly, their feedback was pretty mixed in terms of how in-depth they went. Often, they'd just link me to posts from other real-life experts to the point where I felt like I was getting most of the 'juice' from outside of Udacity.