Save this XML somewhere like $HOME/Downloads
alongside the Anka .pkg file.
Install/reinstall using this xml to enabled nested virtualization with the Anka command line installation instructions:
sudo installer -applyChoiceChangesXML nanka.xml -pkg AnkaBuild-1.4.3.104.pkg -target /
If your hardware supports things properly, you should be able to install Docker for Mac inside the VM and use it.