During the Controni/Violi years, where they were having trouble with Rizzuto not following rules, failing to show respect and generally acting like he was part of a totally separate organization, Paolo Violi made multiple attempts to remedy the situation bitching to New York Bonnano heavyweights Nat Evola, Phil Rastelli and Mikey Zaffarano. They could do nothing. Hitting Nic would require approval from Italy.
He went so far as travelling to Agrigento, Sicily to meet with Joe Settacasi, the local mafia don there, to appeal to him. In reality he was never going to go against one of his own.
If Nic Rizzuto had been only made in the Bonnano's, his killing would have been a local matter, approved by Controni,effectively the Montreal capo, possibly cleared through NY, and handled.
The fact they couldn't, shows Nic ultimately answered to Sicily, and was involved in an entirely different game to the one Violi was playing....Sicily needed their own on the receiving end of the drug pipeline, not the American bonnanos.