Enabling Nested Virtualization on a VM hosted by Hyper-V

Let's say you have a VM hosted by Hyper-V named CICDSRV01 and we want to enable nested virtualization to run another Docker for Windows instance, we first need to enable this feature by setting ExposeVirtualizationExtensions to $true on the target VM's processor

# Check if VM named CICDSRV01 supports nested virtualization
Get-VMProcessor -VMName "CICDSRV01" | Select VMName,Count,ExposeVirtualizationExtensions

VMName    Count ExposeVirtualizationExtensions
------    ----- ------------------------------
CICDSRV01    12                          False

The ExposeVirtualizationExtensions property reads False so let's enable it

Get-VMProcessor -VMName "CICDSRV01" | Set-VMProcessor -ExposeVirtualizationExtensions $true

Then to verify whether it has properly enabled

Get-VMProcessor -VMName "CICDSRV01" | Select VMName,Count,ExposeVirtualizationExtensions

VMName    Count ExposeVirtualizationExtensions
------    ----- ------------------------------
CICDSRV01    12                           True

To enable nested virtualization for all machines

Setting

Get-Vm | Get-VMProcessor | Set-VMProcessor -ExposeVirtualizationExtensions $true

Getting

Get-Vm | Get-VMProcessor | Select VMName,Count,ExposeVirtualizationExtensions