Atlach-Nacha vs Cathleen Bate: who would win?

Atlach-Nacha favored — Favored (~65%)

Atlach-Nacha · Cthulhu Mythos · Base

Tier: HIGH 6-B
Attack Potency: Large Country Level
Speed: Unknown
Durability: Large Country Level

Cathleen Bate · My Hero Academia · Base

Tier: HIGH 6-B
Attack Potency: Large Country Level
Speed: Relativistic+
Durability: Small City Level, up to Large Country Level

A heuristic estimate from normalized VS Battles Wiki stats: tier, attack potency, speed and durability.