Reno Ichikawa vs Nagisa Momoe.: who would win?

Nagisa Momoe. favored — Slight edge (~55%)

Reno Ichikawa · Kaiju No. 8 · Numbers Weapon Suit (Post-Training)

Tier
7-A, up to HIGH 6-A
Attack Potency
Mountain Level+, up to Multi-Continent Level
Speed
High Hypersonic, up to Sub-Relativistic
Durability
Mountain Level+, up to Multi-Continent Level

Nagisa Momoe. · Puella Magi Verse · Law of Cycles Assistant

Tier
7-A
Attack Potency
Mountain Level+
Speed
Massively Hypersonic+
Durability
Mountain Level+

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