I think you can apply for a China X Student visa with the following documents:
1. Qualified original JW202 Form issued by the relevant Chinese Government or authorized departments and original Admission Notice from the receiving school with the seal and signature;
2. Original guarantee letter from applicant's sponsor in Nigeria and original recommendation letter from two experts and certificate of graduation (Diploma);
3. Physical Examination Record for Foreigners, if the applicant intends to stay in China for more than 6 months. The record should be done by a local hospital, notarized by a notary public, authenticated by the Ministry of Foreign Affairs of Nigeria, and authenticated by the Chinese Embassy or Consulate.
4. Your valid passport with at least 6 months validity and 2 blank pages left.
5. A ful-filled visa application from affixed with a passport-sizes photo.