For MBA program, scholarship isn’t usually awarded. However, following universities in UK have provisions for Nigerian student to obtain a scholarship even for the MBA program:

The University of Hull
The University of Sheffield
Bournemouth University
University of Glamorgan
Swansea University
Liverpool Hope University
University of Gloucestershire

These are the universities which may give you some scholarships for being from Nigeria. But, getting scholarship isn’t still easy. You must have exceptional previous academic performances or high GMAT score to obtain scholarships offered by these universities.