Nano Server never disappeared and is still going strong in container world :). It's available as Nano Server container as one of the Windows Base OS images: Recently we have made a few enhancement: 1) Nano Server container images released with Windows Server 2019 is now supported for 5 years to Jan 2024 ; 2) Nano Server container image released with Windows Server 2022 will be by default supported for 5 years.

What do you use Nano Server for?