Command and operational use
Section 218(2) · 1999 Constitution (2004 edition)
What Constitution says
(2) The powers conferred on the President by subsection (1) of this section shall include power to appoint the Chief of Defence staff, the Chief of Army Staff, the Chief of Naval Staff, the Chief of Air Staff and heads of any other branches of the armed forces of the Federation as may be established by an Act of the National Assembly.
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 97. Original document
Release: draft-c8d50d87fae9. Source scope, review and corrections