I haven't seen this mentioned anywhere and had it spoiled for me by Supergirl Radio, but Supergirl is apparently pulling a page from the L.E.G.I.O.N. comics and introducing the heroic 21st Century ancestor of a Legion of Superheroes character via Nia Nal, having designed her to be the ancestor of the Legionnaire Nura Nal, right down to sharing/potentially sharing codenames.... which is really rather neat.