Q. Can I switch between Nano server and Server Core in vNext?
A. No. Like when Server Core was first introduced in Windows Server 2008, during installation the choice is made between Nano server or Server Core and you cannot switch between them post installation. This could change in future versions so that it behaves in a similar fashion to Server Core/Server with a GUI in Windows Server 2012 that enables easy switching between configuration levels. For vNext think of the deployment choices as the following: