Documentation is one of the biggest risk areas in Nigerian property transactions. Before paying for land, ask for the survey plan, deed of assignment, root of title, tax receipts where relevant, and evidence of government consent if applicable.
A Certificate of Occupancy is useful, but it is not the only document that matters. You should also confirm whether the land is under acquisition, whether family representatives have authority to sell, and whether the physical boundaries match the survey.
Work with experienced professionals for legal searches and physical inspection before committing funds.