Taxable persons in Nigeria can check their TIN online. Note that the JTB website address; tin jtb gov ng for TIN registration and validation is inactive.
Joint Revenue Board (formerly JTB) and the Nigeria Revenue Service (formerly Federal Inland Revenue Service) have made the procedure easy. Below is the link to the JTB validation portal;
You will require National Identification Number to retrieve the TIN of an individual or registration number from the Corporate Affairs Commission for non-individuals such as companies, businesses.