Nigeria dwarfs South America: about 911,496 km² km² against 17,840,000 km² km². At true size Nigeria is about 19.6× larger — the whole of South America fits into Nigeria roughly 19 times.
The old Mercator map treated both about equally (1× vs 1× inflation), so at least their relative sizes were preserved — even if both were drawn at the wrong absolute scale.
Nigeria fits 19× into South America.