Nikon hasn't had a lot of success in the mirrorless camera market because they've yet to develop a good mirrorless camera. Samsung makes some quality mirrorless cameras and has developed some pretty good sensors, but their sales have been lackluster. Perhaps Nikon's logo on Samsung's technology could result in the sales that Nikon has been hoping for. And I'm sure Samsung is happy to take Nikon's money.
All of this is rumors. You know how that goes. Only time will tell if it's true or not.