Very unlikely IMO, smartphones have become far too commoditized*, every ODM (even Samsung) is struggling to turn a decent profit, only Apple's still doing kinda okay. Plus, everything Nokia has said/done to date suggests they're not interested. They may get back into some form of consumer electronics, but they'll try to break new ground, not plant in exhausted soil.** Much of their business going forward seems to be in the IP licensing game, low level (high costs) research, then licensing out those findings. That's their advanced materials division (can't recall latest name OTTOMH), they still have HERE & NSN of course.

Plus, some users seem to have short memories, or they didn't follow the entire Nokia + Maemo/MeeGo saga from the earliest days. Nokia's one of the last co's I'd want heavily involved with Jolla/MeR/Nemo/Sailfish. There's many rising Asian/Other ODM's (mostly Chinese -but not exclusively) currently riding the Android wave, who I'd much rather see embrace MeR/Nemo/Sailfish before Nokia. Of course, Jolla should go with Nokia*** if they're unsuccessful in wooing other ODM's & Nokia's one of the last options, after all, beggars can't be choosers. ;-)

*not-to-mention insanely competitive, at least on the hw side
**and already there's been (very vague) hints at what they might do
***assuming Nokia's ever interested, which I highly doubt