Not in a way you’re probably going to like.
You could set up a bare metal hypervisor on the system and set up a VM for your NAS, Windows, and Linux and swap between them as needed, but uh, that’s not really an exceedingly pleasant desktop use case, for a number of reasons, one of which is that you really won’t have the normal ‘sit down, and use the computer’ desktop experience.
Alternate option: run the NAS and either the Linux or Windows install in a VM, and keep it booted into, say, the desktop Linux environment with everything else being a virtualized setup.
Fair, but he said he wants to move from Windows to Linux, so I just assumed there wasn’t going to be any of those since, well, they’re not going to run in Linux anyways.