This is my first mobafire build and i have done it to Nasus, one of the best champions in lol.
I hope that u dont dislike only because it is my first one.

This build does better dmg when you farm you Q much. If you have 50 last hits in it at mid game you will do just fine if you dont forget keep farming it more towards late game. If you are at top lane I think that you may want to take blue buff every time it has spawned do it might be worth of buying some wards to help you get blue and help you avoid enemy jungler (if they have jungle).

There is no runes added yet because i have just ap and ad page and i use ad page at Nasus.

Masteries are quite tanky but i have little ad but i took Weapon Expertise because Q deals physical damage.

Nasus is very good team fighter but you MUST BE THERE because you dont help a lot if u are somewhere farming you Q. You just pop up whit your ultily and put spirit fire to do terror to you enemies.

This build allows you to go pretty much anywhere whitout being worry about enemies. I have my self do many 3v1 triple kills and still have over 70% health at this build. And i guess that there is no champ what can kill you 1v1 (you have enough movement and health to escape something like extremely feeded Teemo what blinds you and does extreme high mixed ranged dmg)