I haven't been able to test this using C2's built in node webkit export because of my antivirus flagging it as a false positive, but here's a way I just tested:
Download node webkit from it's web page, extract it from the zip file
Open nw.exe
Open a C2 game, press preview
Copy the address from the window that comes up
Paste it in node webkit's address bar, add ?nw to the end of it, hit enter
Press preview in C2, and it updates the node webkit window
Close the browser window that you copied the address from