Alistar vs Nautilus Support Matchup
Alistar Support wins 53.6% of 4,306 Low Elo games against Nautilus Support, +1.9 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 Alistar is favored
Alistar's Headbutt(W) can knock Nautilus away from his carry and break the follow-up to an engage, while Unbreakable Will(R) removes crowd control and reduces incoming damage. Those tools let Alistar absorb or reverse the commitment that Nautilus needs to win the exchange.
How to play as Alistar
Hold Headbutt(W) to peel Nautilus off your carry after he commits; do not use it to knock a target away before your team can follow.
Use Unbreakable Will(R) when Nautilus's crowd control lands or when you need to tank the rest of his burst, rather than activating it before the engage.
Headbutt(W) can displace Nautilus away from Alistar's carry after he engages, and Unbreakable Will(R) removes crowd control while reducing incoming damage.
How to play as Nautilus
Expect Alistar to peel your first target; look for a catch on the carry when Alistar has spent W, or wait until his R damage reduction ends before re-engaging him.
Nautilus's engage depends on reaching and locking down a target, while Alistar has a targeted knockback that can interrupt the follow-up.
Sources
These notes come from r/alistarmains, checked against the champions' abilities.