Pettis didn't break his hand vs Ferguson. A broken hand would require to be reported by the athletic commission and would result in a medical suspension. Every time, not up for debate. And there was no broken hand reported. Maybe his hand hurt, but we all saw the reason that fight ended. Pettis was getting absolutely massacred the last 3 minutes of that round. And he knew he was slowing and Ferguson wasn't going to slow at all, and in fact would likely increase the beating.
I agree Pettis isn't a tune up fight, the guy is a former champ with a ton of talent (and incredibly underrated grappling that nobody seems to talk about). But when faced with huge volume and pressure he's shown he'll wilt at times.
Now, that said, I don't think Nate is capable of doing the damage that Tony does. Nate can pour on volume, but it doesn't ruin faces like Tony's. But Pettis also wilted vs Max (again, a special fighter and Pettis was stupid in cutting that much weight and fighting at 145). If Nate really puts volume on Pettis it will be interesting to see how it plays out.