Election: single presidential candidate
Section 133 · 1999 Constitution (2004 edition)
What Constitution says
A candidate for an election to the office of President shall be deemed to have been duly elected to such office where, being the only candidate nominated for the election - (a) he has a majority of YES votes over NO votes cast at the election; and (b) he has not less than one-quarter of the votes cast at the election in each of at least two- thirds of all the States in the Federation and the Federal Capital Territory, Abuja
This is the 1999 Constitution as published in 2004. Later amendments aren't included yet, so a section may have changed since.
Original source
Official Gazette · CFRN 1999 official PDF · printed page 67–68. Original document
Release: draft-c8d50d87fae9. Source scope, review and corrections