Actually it is not the same problem.
Let me explain: in case the file is hosted on your machine, you can sudo (or use Super Empty Trash) to delete it overriding almost every block.
In your case the file is hosted on a remote File System.
If you sudo on your machine you become the root of your machine, while the issue is on a remote file system.
Regardless of the fact that there is an error or a permission issue, your identity on your machine is totally irrelevant on the remote file system, only your login credentials (used to mount the share) are relevant.
If your NAS can be wired in some way to a machine, and used as a single Hard Drive, then you'll have option to sudo, fix, delete and whatever.
The only other option is to act from NAS host perspective, i.e.: through its web interface.
In every case, to fix this type of issues you are asked to host the File System involved.