To connect to an NFS share, you need to make sure you have the NFS client installed. This component is a part of the Services for Unix component. Go into the control panel, Programs and Features, then Turn Windows features on or off. Make sure Services for Unix-based Applications (DEPRECATED) is checked, and click OK. Be advised that typically only Ultimate and Enterprise versions of Windows typically have this component available.
This will install the MS NFS client and (AFAIK) the
mount command. I'm not at work so I can't verify exactly. If I remember I'll update Monday.
If your NAS can enable CIFS or SAMBA style shares, I would use that instead.