Nasus just feels like Gruul in Hearthstone
Yeah he can scale infinitely, but he's just a champion/creature that can die with the appropriate answer no matter how big he currently is (is easily countered/ playable around), and as the powercreep goes on, there are actually much stronger lategame creatures (C'thun, N'Zoth, Yogg...) , except if you really let him alone for a crazy amount of time (equivalent in lol : Nasus is actually meh in teamfights and right now gets outduelled late game by Yi/Jax/Vayne and there are way stronger teamfight hardcarries ... He doesn't real feel tanky or that crazy damage-heavy ; and you can just easily control him with CC (taunts/spells equivalent in HS) )