There is only one file type that uses the .NCL extension:
NirCmd Script File
An NCL file contains a script used by NirSoft NirCmd, a free command line utility used to perform various tasks in Windows. It contains one or more commands in plain text that tell NirCmd which task to perform in Windows.
Here is an example of a command used by NirCmd to turn off a computer:
nircmd.exe exitwin poweroff
NirCmd allows you to perform a variety of functions by executing NCL scripts. Some examples of tasks include restarting or shutting down windows, creating a shortcut to a file, changing display settings, changing the system volume, writing and deleting values and keys in the Registry, or connecting to a VPN network.
Updated: August 31, 2018