The nginx ebuild currently installs locale conversion tables (koi-utf, win-utf,..) into /etc/nginx that could be used as guide when writing your config. I personally can't see any added benefit in cluttering your /etc/nginx for this reason. If we want to install these , we should at least put them in /usr/share bundled with a conversion script also found in contrib that helps you with generating your own conversion table.
fixed in 0.8.34-r1, thanks