Tenure of seat of members (National Assembly)
Section 68(1)(c) · 1999 Constitution (2004 edition)
What Constitution says
(c) he ceases to be a citizen of Nigeria;
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 49–50. Original document
Release: draft-c8d50d87fae9. Source scope, review and corrections