Nokia did not sell the name 'Nokia' to Microsoft, and from January 1, 2016, is free from Microsoft's shackles to sell mobile phones again. Microsoft can't sell "Nokia Lumias", only Microsoft Lumias.
The option remains open to, for example, purchase Jolla and in doing so, regain much of the former Nokia team and (and their funky Linux from Finland, where it all started...) and use the modern version that's available to them of the OS that once was Harmatten/Meego, that drives the awesome N9/N950.
In fact some of the funding to start Jolla came from severance packages to the team that was laid of by Elop, having delivered the N9, in spite of Elop's interference and obstacles on the way to enriching himself and his masters.