It seems Xsteel CAD files (.nc1) are supported in Autodesk AutoCAD (possibly with a plugin) and as such, it should be possible to convert them to IGES product files (.igs, .iges) or other similar formats. Sadly, we haven't found any other relevant information for this conversion or other programs
Convert Xsteel CAD drawing to IGES 3D exchange format.
We found 2 software records in the database related to .nc1 to .igs file format conversion.
Microsoft Windows software - convert nc1 to igs on Windows
Leading 2D and 3D CAD development software from Autodesk
Convert from nc1 file format
The tables with software actions are a good pointer for what a certain program does with various file types and often may give users a good hint how to perform certain file conversion, for example the above-mentioned nc1 to igs. However, it is not perfect and sometimes can show results which are not really usable because of how certain programs work with files and the possible conversion is thus actually not possible at all.
Apple macOS / Mac OS X software - convert nc1 to igs on OS X
Mac version of popular Autodesk AutoCAD software