The .nwm file extension is used to indicate an ERF file that is a BioWare-made module that can be played within Neverwinter Nights. These files implement both the official campaigns and the premium modules.
NWNWiki
The .nwm file extension is used to indicate an ERF file that is a BioWare-made module that can be played within Neverwinter Nights. These files implement both the official campaigns and the premium modules.