You maybe onto something in regards to suing the UFC if they don't book the fight. He's the interim champ Conor is the supposed champ in the same division. Combat history says the interim belt must be unified that interim belt should be Tony's front of the line pass to now challenge the newly disputed champ with a co-Champ now in the picture, unless there's special circumstances and Nate is not a special circumstance.
I'm not a lawyer I just play one on Sherdog, but I've heard of dumber workplace lawsuits being litigated on in courts.