Nasus vs Heimerdinger Top Matchup
Nasus Top wins 54.7% of 1,231 Low Elo games against Heimerdinger Top, +3.3 points vs expected, 2-patch window 26.19-26.20.
Researched on LoL patch 26.20. Tips are written to hold at any rank; stats come from Low Elo ranked games up to patch 26.20.
Why Nasus is favored
Nasus can damage Heimer's turret setup with Spirit Fire(E) and earn Siphoning Strike(Q) stacks from turret kills, so the structures that drive Heimer's early lane pressure can also feed Nasus's scaling. Nasus's life steal helps him recover from poke, and Wither(W) makes it difficult for Heimer to kite once Nasus closes in.
How to play as Nasus
Use Spirit Fire(E) to damage Heimer's turrets, and take Siphoning Strike(Q) stacks from a turret only when you can step in safely. Nasus players recommend clearing turrets with E and Q, while Heimer players warn that your Q last-hit is easy to read for his grenade.
Siphoning Strike(Q) can grant Nasus stacks for killing Heimerdinger's turrets, and Spirit Fire(E) can damage them; Heimer mains describe Nasus's empowered Q attack as a way to remove a turret.
Soul Eater(P) gives Nasus life steal, which helps him recover from Heimerdinger's turret poke; players in this matchup describe Nasus out-sustaining Heimer once he survives the early pressure.
How to play as Heimerdinger
Keep your turrets set up while Nasus is last-hitting, and save CH-2 Electron Storm Grenade(E) to directly hit him when he steps up for Siphoning Strike(Q); players note that the Q last-hit is telegraphed and the direct grenade hit stuns.
Sources
These notes come from LoL Wiki, r/nasusmains, r/HeimerdingerMains, and r/topmains, checked against the champions' abilities.