Nasus doesn't really need nerf. All that u are telling its truth, that no matter how much u stomp him early, he will come back, with decent stack dmg and overall 1v1 beast. He can't be really beaten by bruiser(maybe except 2-3 champions) 1v1 in the mid game if he is playing correctly. U can just stop his farming and deny to the moment when everything just go in the other direction.
But to the point why he doesn't need a nerf?, he lacks mobility. He is only a moving meatshield in the teamfights. No matter how much stack he got. He can even has 1000 stack on q, but he will be useless in teamfight, he will be good 1v1 vs bruisers and some ad carries, good split pusher but shit in teamfight.
His moment to shine comes in the mid game , not really late game, when he finished trinity, and builds tanky + his ult resistences, in this moment he is a raidboss, because no one even buys penetration in those moments of the game, everyone just goes core builds and thats often the mistake of people who for example playing as an adc goes 3 crit items instead of rushing
or
after 2 crit items when seeing raidboss nasus, same with void staff as on mid because nasus with R around 11 lvl has 150 armor/mr + and around 2.5k hp. He falls of late( YES HE FALLS OFF LATE GAME) hard to belevie lmao, when the amount of dmg cc, in teamfight are just insane, nasus dies in a 3 sec on a teamfight, he won't even catch anybody while being bursted by enemy fire. Everyone has builded penetration in this moment of the game. The only thing he scales late game is his Tower pushing, and if u really won't go in on him 1v1 then u won't die. At this point of the game there are several champions who are almost equal to his late game 1v1 and can hold im off while the rest is just nuking him.
The funny fact is that every bruiser u mentioned is way better to just kill enemy backlane than nasus, and that should be their job, not fighring with nasus. Let the mage and adc deal with him, they just have amount of dmg to fuck him up.
If your team is braindead, cus its gold i get it . Look at the mid and your bot champions. if u have

on mid then nasus will have really hard life regardless of their feed. Other mages are good too but they need a bit of items and time to fuck him up while these just melt nasus, and have enough cc to just stop him and make his life a nightmare, same with adcs.
On bot


On top: I think that good
can even 1v1 him in late, due to her sustain conqueror etc, in previous seasons i think it would be impossible but now, its bullshit, if any diamond+ riven otp is here, pls tell me if im wrong.
Champions that can outscale him in teamfight :
{{champion:420}

} ,just almost anybody, also almost all of these champions shits on him in early game. This post is just too long so I end it.