Would be great if the patents were invalided, but the bigger issue would be them being accepted in the first place. That shouldn't even work.
If this does go to court because the patents are considered valid and they can successfully argue that they don't apply, I'm afraid Nintendo could just hand-craft another patent. They would have been given instructions the recipe during the court proceedings.
But I do wonder if PocketPair could just default on the lawsuit in the US. What kind of effect would that have?