Connecting to a NAS device via NFS on OSX is largely the same as connecting via SMB or AFP with some minor differences.
Note: NFS will allow access to private folders if this protocol is enabled for that Share.
1. Click on "Go" in finder
2. Click on "connect to server"
3. Enter the following "NFS://<device name or IP>:/shares/<share name>"
4. Click "Connect" and fill in a username and password when asked for them. (This is the NAS user, not the Mac user.)
The whole line must be entered, and capital letters included where applicable.