I'm going to quote someone who has a pretty high elo... I'm pretty sure that it was Gbay99... also, pretty sure I meant "paraphrasing" as well, but moving on!
"I noticed that my soloqueue games are actually shorter at higher elo, because both teams usually make fewer mistakes, and mistakes are more properly punished. People know how to use their advantage that they get from kills in lane to capture your objectives, much more so than in Bronze or Silver."
Nasus is terrifying only in the late game. Even if he doesn't make any mistakes at all, that doesn't mean he can't get bullied out of his farm. Remember, if he can't farm, he is going to fall off. Hard. That's the main counterplay to Nasus, denying him farm, and ending the game earlier. He's really not that much of a problem. Rather average top if you play against him correctly.