As written in a previous post, the nested virtualization will be one of the future features of Microsoft Hyper-V. Actually Microsoft simple does not support nested virtualization in its Hyper-V product. Nothing wrong with it, but it’s a case where not supported means also that it simple does not work at all. And usually for production user cases it’s not necessary. But for testing and labs this features could be really useful, expecially in the client side of the hypervisor. In fact this feature has already been added to Windows 10 (starting with  the build 10565 of Windows Insider version).