same thing here... c2 226, latest v0.13.2 nw.js - avast marks nw.exe as a threat. whitelisting nw.exe in avast is ok for me. but telling all the players of my game to do the same seems to be a very loosy workaround...
i've sent the exported nw.exe to avast hope they'll do some magic with this. everyone with this problem repeat!
Of course you can't ask the players to do that. You'll lose customers. I hope that Avast fixes this soon (or it will be fixed with the newer NW.js versions). If not, then we might have to contact Avast directly in that matter.