My pick is that Ma'a Nonu will stay with the Highlanders. There's two reasons for that: Jamie Joseph is still prepared to take him on and the other is probably no one else is.
Nonu's burned his bridges at other places-like the Hurricanes and the Blues. I note that Mark Hammett has said he would 'never say never' but I'd be surprised if Hammer wanted to bury the hatchet there. The Blues story, where he shook Sir John Kirwan's hand and then took off to Dunedin has been well documented. At both franchises there were hints of divisions and politics with the team.
I doubt the Chiefs want him, even if they don't get Sonny Bill Williams back next year. Again, never say never but I can't see Dave Rennie wanting to import any problems into a successful team and culture. When Crusaders assistant coach Tabai Matson was asked what he thought of Nonu's spear tackle on Tom Marshall, his body language looked like he'd been asked to swallow a cup of cold sick. I don't think the Crusaders want Nonu either.
There have been some real problems out of the Wellington side Hammett inherited. There seem to have been a few players in that side with a certain mindset and they've been tainted a bit, I'd say.
For example, you'd wonder why Andrew Hore wasn't leading the Highlanders against the Hurricanes last night. It's his old franchise, he's got a point to prove and he's their captain and a senior player. Yet he was on the bench. Why wouldn't you start him? There was no mention of any injuries. You can't tell me it's because he is an impact player.