Reinstalling NixOS on the same machine

suppose I saved my /nix/store dir with

nix-store --dump /nix/store > some_backup_file
nix-store --dump-db > some_backup_db

is it possible to use some_backup_file as repository during reinstallation of NixOS on the same computer without reconfiguring hard drive?

and, in general, is it possible to use somebody’s dump file as local repository?