Create an npm project in github using the guide here:
Publish the release. You should then see your npm package published in the "packages" section of the web UI when looking at your github project.
Once you've got a package published, edit the package.json file and bump the version, commit, and release again, and then do that a third time.
Create an access token in github with "packages:read" privilege.
Create an npm proxy repository with remote of "https://npm.pkg.github.com" in Nexus Repo. Configure authorization in that repository using your token, plus your github user ID.
Now try to install the latest version you published using npm.
That will work.
Try to install the previously published version:
That will fail.
The logs for the second attempt will show that it successfully download the package, but it deletes it for some reason that is not logged, and then returns a 404.
Note: This may have something to do with the fact that github npm registry does not follow standard naming conventions for package tarballs. They are published with this style of name:
Expected: Npm works with this remote registry, so Nexus Repo should also.