I thought providing further feedback would be helpful. As this long requested feature still hasn't been included I've cancelled my premium/plus subscription and am using a different note taking app which includes nested tags in the iOS version. Evernote has a lot of great features, though it is perhaps becoming a little clunky, but as it prevents the tagging method of organisation being easy to use from an iOS device it isn't quite a useful to me as some of the competition.
Cheers.