Nigeria is looking for $50 billion dollars in missing oil cash. Apparently someone at the Nigerian National Petroleum Corp misplaced the cash.
"The NNPC failed to remit to the government 76 percent of oil revenue earned from January 2012 to July 2013"
Not all of it is missing oil money. Some of the money is missing because oil was exchanged directly for refined product. And even if that is the case it's still likely that some of the refined product was itself stolen from the government. But even though there are probably quite a few Nigerians with this misplaced money, it's pretty unlikely that they need access to a random US bank account. I'm pretty sure they've already figured out how to get it out of the country on their own.