The answer is yes, and no. Yes, it provides this feature and you can change location of the store, but when you use custom location, you won't be able to rely

The answer is yes, and no. Yes, it provides this feature and you can change location of the store, but when you use custom location, you won't be able to rely on the precompiled binaries and will end up recompiling everything. This is because when nix links shared libraries it modifies binary to point back to /nix/store/... location. This way it is completely isolated from the rest of the system. Normally nix won't allow you to place a symlink /nix to point to other place, because while it mostly works, some packages that are resolving symlinks to actual path might end up being broken. You can define an env variable (forgot what it was, but you should be able to find it by searching the error message) that allows you use this setup. This actually was an issue when OS X Catalina first appeared. In that version Apple made root disk read only and also wiped anything that was manually created. Ultimately the solution was to create a /nix as a mount. The nix installer does it on mac (in the past you needed to add an installation option, not sure if that's still needed).