Nigeria covers 911,496 km² km² on the new Equal Earth world map — 0.7%% of all land on Earth, making it the 33rd largest country in the world and the 14th largest in Africa. At 10° latitude Mercator only inflates Nigeria by about 3%%, so the old and new maps largely agree on it — unlike the far north, where Mercator's stretch is dramatic.
For scale: Nigeria is roughly the same size as Venezuela (914,310 km² km²).
You could fit 3 of Italy inside Nigeria.