I am answering my own question. In a nutshell it is no longer supported
.NET Core 2.x and 3.0 images are supported and available for all supported versions of Nano Server starting with version 1709. This means that the 2.x and 3.0 manifest tags can be used on Windows 10, version 1709+, and Windows Server, version 1709+. You can also use non-manifest tags for those versions, too.
https://devblogs.microsoft.com/dotnet/net-core-container-images-now-published-to-microsoft-container-registry/
You can still use the unsupported nano server 2016 for windows server 2016 using this
docker pull mcr.microsoft.com/dotnet/core/runtime:2.2-nanoserver-sac2016