Once upon a time there was LING (also known as Erlang on Xen), however this project seems pretty dead nowadays. There are other unikernels like Rump that have examples for Erlang. My problem with NanoVM is that it is closed source while there are other, open-source, projects that supports such approach.
In general from what I see the idea of unikernels pretty much died out (that is a shame) and waits for better times.
From the “high level” viewpoint the Nerves is the most unikernelish thing in the Erlang world right now.
And IMHO Erlang is perfect environment for unikernels runtime language, as it is mostly a operating system on it’s own, so removing one layer (“real” OS) wouldn’t harm 90% of Erlang applications while it would provide obvious benefits.