Current image is quite large, not quite certain how much space the NordVPN client uses, but I'm sure the final image can be quite a bit smaller than the current ubuntu image.
NordVPN client is fairly large and makes up for at leas 80% of the image size. Switching out Ubuntu for Alpine will change maybe a few MB in total, which isn't worth the hassle.
Current image is quite large, not quite certain how much space the NordVPN client uses, but I'm sure the final image can be quite a bit smaller than the current ubuntu image.
Maybe switch to Alpine with s6 if possible?