This is my first guide here so don't be so judgemental and. Nasus could be played many ways but I prefer the full tank way, because he is an amazing tank even without his ultimate. Usually I play Nasus as solo top because if he gets farmed he will be unstoppable.

P.S. Does anyone know how to add images(flash, ghost and items)into the build?

Thanks for your help

Pros:

Extremly hard to take down
Exellent farmer
Nice AoE ultimate
Passive helps to lane
"Who let the dogs out? Woof, woof!"

Cons:
Dosen't do much damage if Q isn't farmed
Small damage output

Runes are defensive, but you can take Greater Mark of Fortitude instead of Greater Mark of Desolation. But I recommend that the Seals and Glyphs stay the same because those give amazing durability in lane. Dogde seals are all-around amazing.

Begin with Doran's shield because of that armor and regen. You can start with Ruby Crystal if you want to rush your build. I suggest Ninja Tabi but you can go Mercury's Tread if you are afraid of stuns.

By mid-game you should have gotten your Warmog's and already be building Force of Nature. Late game the most important item is Guardian Angel and Banshee's Veil for that extra durability.

Early game:
Doran' shield, Ninja Tabi and Giant's Belt

Mid game:
Warmog's Armor, Force of Nature

Late game:
Guradian Angel, Banshee's and Thornmail

Recommended:

Flash is a great spell. It helps to chase and to escape
Teleport for solo top - priceless.

Could be used:
Ghost instead of flash. This is for those who prefer Ghost
Exhaust can be used to set up ganks or pinning down enemy carries in teamfights

Other spells don't have a good use on Nasus so therefore I don't recommend them.