As docs are saying
The symbol files (.sym) can be extracted from the downloaded packages.
As far as I understand from one of this http://nwjs.io/downloads/ or from one provided by the nw-builder. Both have the same structure without any *.sym files. And there is no clue how to extract them. Nor in the docs nor in the www.
stackwalk-http is a version of minidump_stackwalk that can fetch symbols over HTTP, and also has the Mozilla symbol server URL baked in. If you run it like stackwalk /path/to/dmp /tmp/syms it will print the stack trace and save the symbols it downloaded in /tmp/syms. Note that symbols are only uploaded to the symbol server for nightly and release builds, not per-change builds.
There is a link to "Binaries for other platforms" in release notes.
For example at page http://nwjs.io/blog/v0.17.4/ there is a link to https://dl.nwjs.io/v0.17.4/ which contains symbol files we are looking for.
