I have never heard of this case before, but the appeal has just gone to the judge.
In summary, a BVI-based company entered into an agreement for Nigeria to supply it with gas, which they didn't do, so hav ing spent a fair bit of cash up front, it was awarded $6.6 Billion plus interest, which now is pushing ten billion - a fifth of Nigeria's foreign reserves.
The Nigerians, with supreme irony considering they are a bunch of international fraudsters, are claiming that the deal was bent.
The cash order was converted to a judgement to seize assets back in September, and the appeal has just finished and is with the judge.
I would truly laugh my tits off if they ended up losing, given that the government of that country has basically given a green light to massive amounts of international financial fraud since before the fucking Interwebs was even invented.
But it's a complex case, with jurisdictional arguments aplenty and the Nigerians hysterically claiming they have been scammed - presumably because they couldn't get their own grubby mitts on any cash involved.
Explainer: Nigeria fights back, but threat of $9 billion penalty looms - Reuters