I dug around on the nw.js forums. Apparently, some file in the "manifest.json" ? or "package.json" ? (I'm not sure where these live in the filesystem, if you do, please tell us), can become corrupted, and can "blacklist" the name of your app.
Changing the "Name ______ " of my project in "Project Properties" instantly solved the problem.
Could you try and let us know?