Hello welcome to my AP nasus guide it might not seem like it but your E Spirit fire and your ult Fury of the sands will do way too much damage to handle i was in a game with AP nasus and i got 21.7.3 and the enemy team said AP nasus? BS well i just told you otherwise.

The runes are standard AP with a little bit of tank so you can survive late game when you will be squishy but you can change the marks to Greater mark of replenishment so you can survive the early to mid game.
you can also change seal to some Greater Seal of intellect to survive early to mid game.

Standard AP masteries with some tank so you can survive team fights but you can change them to more offensive so you will do even more damage.

You need the Death fire grasp or else you wont do so much damage and you NEED athene's holy grail cus you run out of mana fast as AP nasus the lich bane is super usefull cus your Q will do alot more damage cus you get like plus 500 damage with it.

Well what can i talk about this you need your E first and then your Q so you can do alot of damage.

this are good options but you can chose ghost and teleport or ghost and ignite.