I'd suggest reporting it directly to the NW.js team. A specific NW.js version breaking it, while it works in the Chrome browser, is potentially evidence the problem is in NW.js itself, in which case there's nothing much we could do about it ourselves.
It may still conclude as being a graphics driver bug. It's entirely possible that the graphics drivers have always been broken, and a Chromium engine update tweaked some graphics code that is in fact written correctly, but then started to run in to a graphics driver bug on your system. (Figuring out who's at fault in this situation is tricky - people often assume it's definitely NW.js' fault in a situation like this, but it's not definite, it could still be a broken graphics driver, and I would say that's pretty likely given the general quality of Linux graphics drivers.)