I don't think Nate is leaving any time soon. I remember seeing an interview with Kyle Prior a little while ago when he was asked if he had ambitions to go to Hollywood like Steve Peacocke (Brax) & others. I am sure though that he said something like he might try over there one day down the track, but he had no plans for the foreseeable future (& therefore would be on H&A for sometime yet).
Yes, It would seem pretty certain now that he will get back with Ricky at dome stage.