Kazumi vs Chion: who would win?

Chion favored — Favored (~65%)

Kazumi · Puella Magi Verse · Real Magical Girl

Tier

6-C, up to 5-C

Attack Potency

City Level, up to Moon Level

Speed

Massively Hypersonic, up to Massively Hypersonic+

Durability

City Level, up to Mountain Level

Chion · Nanatsu no Taizai · Base

Tier

HIGH 7-A, up to 4-B

Attack Potency

Large Mountain Level, up to Solar System Level

Speed

Sub-Relativistic

Durability

Island Level

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