Tip
Use [Q] to prevent him from retreating while attacking him with basic attacks to use [P]-[W] to swallow him whenever he closes in. He is an easy kill if [Q] lands as he lacks movement skills.
Tahm Kench vs Nasus

Use [Q] to prevent him from retreating while attacking him with basic attacks to use [P]-[W] to swallow him whenever he closes in. He is an easy kill if [Q] lands as he lacks movement skills.