The game does not seem to want to work out of the box, but it can still be done.
MacOS Mojave: The patch doesn't work unless you patch it under High Sierra first — see below.
Ambrosia SW's servers are still online, version 1.1.1 is the latest for Mac. Install it in /Applications.
DO NOT run it yet.
Ambrosia SW uses expiring license keys for some reason, and I was unable to get new keys in Nov 2018.
So I disconnected from the Internet by disabling Ethernet/WiFi in System Preferences, and set the system date back to the day I received my license key in May 2005. Then I launched EV Nova, and went through registration. It accepted my key no problem — if you have issues, maybe try a different year (sorry I can't be more specific).
EV Nova will appear to start, go to a black screen, freeze, and quit after 10–15 seconds.
Go ahead and reset your system time and re-connect to the internet. The game won't ask you to re-register unless you switch Macs.
Daniel Loffgren has found a solution to the black screen issue: novafix. If you are familiar with building software from source, go ahead and follow the instructions for cloning the repo and compiling.
If you do not have XCode installed or don't know much about Terminal.app, then use the "super-automatic installer" linked in the README.
Either way, it will apply a code patch to the EV Nova application that fixes the black screen issue. You should now be able to run it. If there is some problem with the patch, you can delete EV Nova and re-copy the application from the installer disk image and try patching it again.
As noted in the novafix issue tracker, the fix doesn't compile on MacOS 10.14 (Mojave). I tried building on my laptop running Mojave and can confirm the same error report.
If you edit the Makefile and change i386 to x86_64 then the patch will compile, but then applying it to EV Nova will make EV Nova not run.
However, if you compile and patch EV Nova on a High Sierra system, then copy the EV Nova application to a Mojave system, then it will run fine.
Run this in Terminal.app:
update_dyld_shared_cache
And re-launch EV Nova. Opening the preferences dialog seems to break it and require this command to fix.