Hey folks, I've been really out of the loop when It comes to construct 2 for quite awhile, so I'm not sure if the node webkit issue has been fixed.
However you can get your Linux node webkit exports to work with a simple tweak.
The video below will show you how. (Sorry if I seem a little out of it, I'm really tired). :p
http://youtu.be/gS6uXh2iJwE