Yes. Most NAS devices are able to run a UPnP AV music server on the NAS itself.
The Stream Magic 6 / Minx Xi / NP30 can connect to such a NAS if it is on the same network. Otherwise, you must be running a server program on a computer on your network, which must be able to access the files on the NAS.
Note that some music servers do not serve all files types and some cannot access remote volumes (remote hard-drives).