It is not late, but please start your visa processing now. According to my understanding, they need a business visa to China. The requirements are as follows:
1.One completed visa application form with a recently taken passport photo stuck on it; all the items on the application form should be completed neatly with genuine information; false or incomplete information and illegible characters may lead to refusal of a visa.
2.Visa Notification Form issued by an authorized unit in China (Visa notification refers to the form of visa notification issued by the Chinese government departments, companies and social organizations authorized by the Chinese Foreign Ministry. The Chinese company who gives invitation knows how to get this form).
3.One formal introduction letter from the applicant's company to tell his/her identity， the purpose of visit to China, and supposed duration of stay in China.
4.The original and one photocopy of the applicant's ID card. (The original will be returned at the interviews).
5.The original and one photocopy of applicant's certificate of incorporation. (The original will be returned at the interviews).
6.Hotel reservation in China and round-trip ticket between Nigeria and China.
7. Recent bank statement of account.
8.Photocopy of applicant's passport data page and all the Chinese visas.
9.A complete list of the documents the applicant submits.
10. Any other documents the Chinese Embassy requires.