Based loosely on Tk102's GFF comparison tool, this will basically do the same thing with any .nss file. It will do three things for you:
1. Tell you where the two files were located on the harddrive when you compared them.
2. Tell you how many lines are in the file.
3. Detail which line in the files has the changes, with the line number and original formatting.
When you start the program, you will select two .nss files and then specify what file the changes will be saved to. I have added some formatting to help you interpret the comparison. I've included a picture as an example.
NOTE: You will be given the changes as they apply to the second file, so keep in mind which is the original file.
Before people ask, I figured this could help with making mods compatible(the Improved AI and Droid Enhancement mods come to mind).