Elm Ederne vs Mister Nobody: who would win?

Mister Nobody favored — Slight edge (~55%)

Elm Ederne · RWBY · Base

Tier: 8-A
Attack Potency: Multi-City Block Level
Speed: Ftl
Durability: Multi-City Block Level

Mister Nobody · DC · Base

Tier: LOW 7-C
Attack Potency: Small Town Level
Speed: Unknown
Durability: Unknown

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