does tons of damage and gets insanely tanky, easily managing to towerdive as long as he can land his stun combo and press R. Not only that, but he's good early, mid, and late game. I'm lost when it comes to who I should play against him. Would 
or 
work? This champion is ruining my rank.
and 
are decent picks against him
having the right runes also helps
most commonly I see; Grasp, Demolish, Conditioning/Bone Plating, Overgrowth. (Garen would likely go with Inspiration second, running Biscuit and Cosmic Insight, Nasus would likely go Domination second with Cheapshot and Ravenous Hunter)
Your builds will differ on each of these.
Garen - Black Cleaver, Boots (you decide what you need more), Spirit Visage, Deadmans, Steriks, Titanic
Nasus - Trinity Force, Boots (you decide what you need more), Spirit Visage, Iceborn Gauntlet, [last two items can pretty much be whatever]
