Introduction
For those not familiar with Nasus: He can best be described as a top lane Off-Tank. The unique part of the Keeper is that he does not scale with attack damage or ability power much at all, but rather farm. Even when built full tank a heavily farmed Nasus will kill and put out more damage than anyone. We could even consider him somewhat of an Assassin. This is because if you are able to locate someone alone on the map, they are as good as dead with little chance of getting away due to Wither and built-in CDR. Needless to say, Nasus is a top notch 1v1 champion. If you are a person that has patience, hope, and a thing for being an unkillable wrecking dog: You need to play Unkillable Nasus!
Summoner Spells
This pair of skills give Nasus a safe early game, and unrivaled kill potential in team fights. If you remove a champions main weakness he becomes strong, and that is what these two do for Nasus.
Teleport & Ghost
This set is an old favorite of Nasus players and for good reason. This is because it synergizes with the type of game Nasus wants to have. There is nothing more important to Nasus than farm, and these summoners give him the opportunity to attain it in several ways. Have you taken too much damage to keep laning? Go ahead to base and teleport back in time to catch the minion wave at your tower. Does your team want to do an early dragon? Nasus' ultimate is one of the best abilities to do dragon with, and teleport makes it possible and still get back to your lane. Remember, Nasus has a weak early game but that doesn't mean he can't help get kills. If you notice bottom lane is pushed with your teams ward behind them, go ahead and teleport gank down and get a double kill. Lastly, this ability allows Nasus to split push the entire game, allowing Siphoning Strike to become overwhelmingly strong. So as you can see, this set has it's uses. However, you won't be quite as mobile as the first set, and taking it against certain junglers can be a gamble. In particular Jarvin and others with gap closers.
When to pick Nasus?
Generally speaking, Nasus prefers a few things in his lane enemies:
1. Melee (To be in range of his attacks/ultimate and have no ranged harass)
2. Mana (Limits the amount of harass that can be given to Nasus)
3. Auto Attacks (Nasus is a direct counter to AA champions with )
It's my opinion that Nasus should always be selected if you have a favorable lane matchup to farm in no matter the team compositions. This is because a farmed Nasus can rip through and shut down any enemy ADC in team fights. This is significant because that is the source of most of a team's damage. Almost every team has to have an ADC, and nothing is more frustrating for them than to sit there not putting out damage.
Having said that, it does help when both teams contain certain team compositions that can help reduce the effect of Nasus main weakness. The important words here are : Crowd Control. Nasus needs all the crowd control and initiation he can get from his team, and the least amount from the enemy team. This is because Nasus can be kited hard in team fights if no one can be locked down. If at all possible, having champions like Amumu in Nasus' team will greatly enhance his ability to kill.
When these things come togethor, you'll notice Nasus has "god-like" games because his ability kit is made for carrying late. Simply put, Nasus is THE counter to all attack damage carries and high HP bruisers.
