Dear Mrs Fred.
We are sorry for your situation. But the reason for your visa denied is best known to consular authority. Your document may be geniue in Nigeria, while your invitation letter may not be well processed from china here.Chinese bureau already change the rule and law for application on Business and others visa processing, we donts believe chinese consulate denied Nigerians visa due to virgine passport as been said.
Many Nigerians arrive China here everyday for Business, Study, Tourist.
Wishing you good luck.