Wish to enable nested virtualization for a virtual machine that you are hosting on Hyper-V? Here's how to do that!
Note: Nested virtualization must be enabled on a VM-by-VM basis. As you can see below, you must pass in the virtual machine's name in order to enable or disable this feature.
Enable Nested Virtualization
Set-VMProcessor -VMName name_of_vm -ExposeVirtualizationExtensions $true
Disable Nested Virtualization
Set-VMProcessor -VMName name_of_vm -ExposeVirtualizationExtensions $false