No one can deal with him. You have to send multiple people to deal with the bullshit that is Nasus top right now. He does a bazillion dmg with his Q. TLDR: This game is literal diarrhea right now. Whoever enjoys this shit of a patch is a masochist. RITO FIX YOUR GAME
Try 
with Grasp of the Undying, Unflinching, etc, Second Wind, with Transcendence and Ultimate Hat.
First Item 
. Works great at cutting Nasus's stacks in half as you can perma harass, heal yourself, heal when he W's you, and gain perma max HP. Also means that when you choose not to auto attack, you can have his resist reduced by 25 to just truck him. If he chases you, you can tether him and burn his ult. Once the new 
is in game this will be extremely deadly, because Karma can prevent him from life stealing minions too.
In the current meta, you probably won't completely dominate lane with this, but it works the entire game, vs other lanes too, and you will win the lane more or less. You just won't end it 10/0. You can also add a 
to this build to push up the Transcendence, on hit damage, and it pairs well with Wit's mag resist reduction and attack speed.
I find 
with 
and Press The Attack can turn Nasus into his bitch. You just got to be smart enough not to push your lane, or he'll get easy tower protection.
Even if Nasus gets his momentum, the bullying power will at least make his late game come...well, later.
just abuse his early game
dint let him stack
if you are playing ranged and buy this brokemdisgusting
he can not touch you
respect D slow , it is probably the most powerfull slow int he game so dont go into mele range if you know he can beat you
and ask your jungler to camp him(works on me)
