Using Inkscape 0.92.
I followed the instructions for installation using MacPorts to instal XORG X 11 and Inkscape and created a symlink in the applications folder using terminal.
Installation
macOS 10.13 High Sierra
sudo port install inkscape
sudo port install xorg-server
If you want Inkscape to show up in your Applications folder:
ln -s /opt/local/bin/inkscape /Applications/Inkscape # not pretty, but works
I got the "nothing to do error" when running Inkscape. However if I open Macports X11, I can run Inkscape from within. I had to add Inkscape to the X11 applications menu (customize)
I spent some time trying to figure out how to get Inkscape to call up XORG-Server for X11 and made no progress. I ended up installing XQuartz and it works fine.
I'm just reporting in hopes of helping future Mac users enjoy Inkscape.