It could be an equivalent to the Windows "10000 is enough for anybody" limit on OS X, except by the looks of it, a lower limit.
I assume Apple are aware of any limits in OS X but presumably won't change them, and AFAIK nobody has tested Chromium and there is no bug report at crbug.com, because the focus has been on NW.js.
- if you can repro it in the Chrome browser on OS X, file it at crbug.com (I think this would be preferable if it reproduces there, since it means the issue is in the Chromium engine)
- try the --file-descriptor-limit=10000 workaround mentioned in the NW report
- if you can't repro it in Chromium, try to make a simpler repro to attach to the NW.js report and bump it with that
Not much we can do with this post here, and it doesn't follow the guidelines and doesn't relate to C2 itself, so closing.