Just crushed three games in a row top with Nasus. I haven't picked him in a while due to him supposedly being easily countered, but I decided to say "screw it" and just rocked out. Was a huge presence in all three games, with two of the games having their top pick after me. Maybe it's just that Nasus fits my play style really well(farm for a long long time, then decimate).

So, who is supposed to counter Nasus and why?

Renekton and Rumble come to mind as champions who shut Nasus down in lane.

Garren and GP

Most ranged Champions can shut him down for a while.

If you are forced to tower hug you should still be able to get 2 to 3 Q's farmed per wave. So it is really hard to shut him down entirely. If played well and you don't die to ganks you should do fine till you get to higher Elo's.

The problem is the rest of your team. If they can hold out long enough for your Q to hit for over 500 and for you to get a survivabillity item. Assuming you dont get kited around during team fights while your ult is going you should dominate.

Akali just destroys nasus so hard its not even fun
so does olaf and garen
gp, renek, lee sin do well against him too
and teemo also
And although I havent tested it out I assume riven will be hard matchup

I would say morgana could do pretty well against him.

Garen, Lee Sin, GP, Rumble, Riven, Akali, all give nasus a tough time if they keep harassing him an ddon't let him free farm his q.

Whenever there is one on my team they use spirit fire to farm and their q does no damage.