Point angular app on subdomain to subfolder with nginx
Specifying base-href is only needed for the router if your app is not served from the root location, e.g. http://example.com/sub
In your case, you added nginx rules so that content can be served from a sub folder, but using a "root" location (http://sub.example.com)
So from an angular point of view, everything is like it's served from a root folder, meaning there is no need to specify base-href
I had that problem when I was implementing internationalization of Angular application that needed to be served from different sub-directories for each language. Check my solution on the topic.