A new blog post by the virtualization team informs us that Build 10565 of Windows 10 supports nested virtualization. You can find out the details here http://blogs.technet.com/b/virtualization/archive/2015/10/13/windows-insider-preview-nested-virtualization.aspx. Support for nested virtualization was required to support Hyper-V containers, one of two container technologies that will be available with Windows Server 2016. Nested virtualization is something that other hypervisors have supported, but has been unavailable on Hyper-V up until this point.
Nested virtualization is very useful for scenarios such as demonstrating technologies such as Hyper-V replication without requiring multiple computers. If you’ve ever taken a Microsoft class, you know the contortions that the course authors had to go through to create a lab environment to demonstrate this functionality. It may also mean that in future it might be possible to have a VM in Azure running Hyper-V. At present Azure doesn’t support production checkpoints. Nested virtualization may provide a way of doing that, which would mean a lot of the labs people use that require them to have a specific point-in-time configuration to test with a change, roll back that change, and test again would could be run from Azure rather than on a local Hyper-V Host.