I haven't seen a topic/announcement about this so thought I'd put it out there for people trying to get their last-minute tower appearances. You can now finish the questline to unlock Treasure-master Iks'reeged's treasure room (which is a potentially vast source of Nethershards) in one go/day - it formerly took around a week to finish.
So that's an extra way to get some extra Nethershards for the tower for alts/etc that haven't unlocked it yet.