Nasus can lose plenty of lanes, he just can't lose them obscenely hard. He is really easy to gank since has zero mobility (he's balanced around the fact he has absolutely no mobility), but he needs to be getting stacks. He won't lose lane super hard because if you're getting CDR on him like you are suppose to, it's really easy to get near perfect CS under turret.
But plenty of champions "win lane" against Nasus. And pre 6, he's pretty easy champion to gank. Even under turret, he has little options.
Heimer has a really high win rate, but that doesn't mean he's brainless. Being heimerdinger is just contingent to things like doing damage in team fights, having good CS, and securing objectives. All of those things are correlated to winning in a large scale, hence the high win rate. I play a lot of heimerdinger top, and there is definitely lanes he loses, and lots of games where you find it difficult to be useful later into the game. Usually the most utility you can hope for is a flash -> Empowered Grenades initiation for your team.