How to counter Nasus
Let us take a look on how to beat Nasus. We will look at champions who are strong against Nasus and who are weak against Nasus. Use win rate, gold difference and creep score difference at minute 10 to find the best 
Top champion who counters Nasus. You can already win in champion select with the right counters for Nasus. If you want to know how to counter Nasus then you need to take into account the best picks vs Nasus and the worst picks vs Nasus. This Nasus counter data is based on matches played by Pros on patch 14.21 and previous ones. It is important to see whether Pros counter picked Nasus or whether they played as Nasus.
Champions used by Pros to counter pick Nasus
Looking at the matches from Pros (see table Pros counter picked Nasus) we can see that they picked 
Aurora most often to counter pick Nasus. The matchup Aurora vs Nasus occured 21 times. Nasus has 14 wins and 7 losses in this matchup. Learn how to counter pick Aurora to get another perspective on the data.
Lane outcome for Nasus
When looking at Nasus counters you will notice that win rates alone are not conclusional. Therefore we provide an overview (see table Lane Outcome) where you can see the lane outcome of Pros who played Nasus. The lane outcome of Nasus consists of three outcomes: Win, Loss or Draw. Let's take a look of Nasus lane and match outcome for specific matchups. Considering the lane outcome and the match outcome of a specific matchup, might enable you to find the right counter for Nasus.
Conclusion
Analyze the available data and learn how to beat Nasus. To master Nasus take also a look on Nasus builds and runes for Nasus. Good luck, Summoner!