1443 Nullsoft Scriptable Install System Text (Structured) NSIS (Nullsoft Scriptable Install System) is an open source system to create Windows installers. NSIS is script-based and although it has regular and well defined syntax, there are no magic numbers or header sequences. As such, there is no current means to identify a file as NSIS by binary sequence alone, so identification of this format is by extension only. 195 Artefactual Systems Inc / Artefactual Systems Inc 31 Mar 2014 31 Mar 2014 fmt/644 PUID nsi File extension