Yes, this will work fine. The only limitation is that unlike a proper UPnP server, the USB input gives you a rather basic folder view of the music files when browsing, which is not ideal with a large collection.
It will be pretty much identical to the way you see the attached drive using the USB input on your Nova. The advantage you have is that if you look in the Server input you will see ‘Local Music’ which shows you the same music files on your USB drive, but through a ‘tag’ view which allows you to browse by genre, artist, etc. and to see album artwork. Unfortunately the Musos don’t have this option.