Optimus Prime (IDW 2005) vs Mata Nui: who would win?

Mata Nui favored — Slight edge (~55%)

Optimus Prime (IDW 2005) · Transformers · Base

Tier

HIGH 5-A, up to 1-A

Attack Potency

Brown Dwarf Level, up to Outerverse Level

Speed

Supersonic, up to Immeasurable

Durability

Brown Dwarf Level

Mata Nui · Bionicle · Great Spirit Robot

Tier

HIGH 5-A, up to 4-B

Attack Potency

Brown Dwarf Level, up to Solar System Level

Speed

Sub-Relativistic+, up to Nigh-Omnipresent

Durability

Brown Dwarf Level, up to Star Level

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