The most plain NuGet server. No database required.
Simply place your packages in the "packages" folder with the "name/version" folder scheme. If you did anything wrong, the generator script will warn you.
Then for every new package or version, you run the generator script (php gen.php). Note that you will need to specify a base, but it should be pretty self-explanatory.
The generator script produces a static "www" folder that you can deploy to any web host — they don't even need to support PHP!
For example, you can use a Github Actions workflow to deploy this directly on Github Pages.