No offense, but Nigerians are very famous on the internet and their fame is not good. Reports of Nigerian scammers runs all over the internet or at least ran, will it be good to associate bitcoin with them?
It's not really about their reputation. If they start actually using bitcoins it will bring more capital which means a higher market cap which means a higher price. No matter how you look at it, more people buying bitcoins = price bump. I don't see this being huge though unless the whole country starts exclusively using bitcoins (which won't happen, or if it does it won't be overnight).