root /e/init.d ❯❯❯ update-rc.d NordVPN defaults 1
update-rc.d: using dependency based boot sequencing
insserv: script NordVPN is not an executable regular file, skipped
first, i suggest you to add the entry to the sudoers configurations in /etc to not ask it about password
but about the question, you can add a "run command" (or similar) from the keybindings
the rest of the question sounds like you may need to create a script, where to get the password from an GUI entry and using it with the command, but much easier, you can use a graphical sudo, like gksu, example:
Going through this thread I was just wondering whether you are still needing all these steps to set up NordVPN.
I followed (running 3.7.6 alpha x64) the setup using the tutorial on the NordVPN website concisely and have the connection working no problema as a normal user (i.e no "sudo" required to connect) from either the commandline using "nordvpn" command and/or from network-manager checking/unchecking the vpn connection.
good to know that we can configure vpn without problems with the default internet* configurator provided - yeah all the probably needed extra packages for it (plugins) are included by default