I have been playing with Nano Server again today, and I wanted to enable the Hyper-V role to do some testing with it and I knew that Windows 10 supported nested virtualisation (at last…!).  A quick Google, and it is a quick one-liner in PowerShell (just make sure that the VM is turned off, as otherwise it cannot adjust the VM processor settings):

Set-VMProcessor -VMName "VMName" -ExposeVirtualizationExtensions $true