Where can I write actuarial exams in Nigeria?

The Society of Actuaries, USA (SOA) and the Institute and Faculty of Actuaries, UK (IFoA) have exam centres in Lagos. 

Further information on  these exams are shown 

SOA: https://www.soa.org/Education/Exam-Req/default.aspx

IFoA: https://www.actuaries.org.uk/studying