I am looking at this because I am considering the staging feature of Nexus Pro - the ability to better track which artifacts are ready for production and which ones did not make the cut. Now it may be that CDE does some of this, but I'm not sure. It's really just exploratory at this time.
So - I understand how to make CA RA point to an external repo, but what I'm hoping to find out is whether I can take my existing nolio repo and get it into a new instance of Nexus 3. The docs I have seen imply I can simply copy the sonatype-work folder and re-index the repos, but since they seem to have different folder structures, I'm not certain that will work. I will likely try it out to see what happens.