Is there any stopping a fed nasus?

He heals with autoattacks(that includes Q) also because you are low level people don't know how to kite and you can't really stop him unless your team knows how to kite and people don't know that until you reach a good rank,so your only hope is to either set him behind early

Specific champions can deal with nasus due to their kits later on, even if he gets out of hand early. Examples: Vayne, no matter how tanky he gets she will shred him with true damage, and she will kite him. Trundle, teamfight counter, will steal all his tanky stats for himself, allowing to pop nasus really fast in tf. Garen: Unpopular opinion but I find him really good vs nasus, Q breaks slows including wither, and is on shorter cd and it silences for 2,5s not letting nasus use the q. His E spin shreds armor which combined with black cleaver which is core item on Garen anyways allows him to shred around 45% of nasus armor , thats huge. And finnaly don't underestimate Garen's ult, at rank 3 it basically executes villains from 50% hp, so if Nasus or any other tank becomes a villain, Garen will nuke them from half hp.