There are mainly two types of files to convert, parameter files with readings and related parameters and binary waveform files.
The conversion to Nordic format from some other format will in many cases be to Nordic format and not to Nordic2 since many formats now are rarely used. The most used programs convert to Nordic2 like IMSNOR. If the program converts to Nordic format and you need Nordic2, use program NOR2NOR2 to get Nordic2 format.