A 400-foot nuclear kaiju vs a 400-pound ape. The gorilla is invisible at this scale.
Godzilla is roughly 250,000 times heavier than a silverback gorilla. The gorilla is smaller than Godzilla's toenail. There is no analysis to perform here.
Godzilla might not notice the gorilla exists.
The gorilla is strong for a primate. Godzilla is a nuclear-powered kaiju the size of a skyscraper.
Godzilla wins by default. The gorilla is too small to even register as a threat.
Godzilla also fights
Silverback Gorilla also fights