Nigeria dwarfs Oceania: about 911,496 km² km² against 8,600,000 km² km². At true size Nigeria is about 9.4× larger — the whole of Oceania fits into Nigeria roughly 9 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 9× into Oceania.