Honestly it’s a good matchup, Valdez was good but I’m not sure he’s ever been at such a size disadvantage like he is here. Nino is used to being the bigger man but Carnera was nearly 50 pounds bigger and 3 inches taller with a lot more muscle. Even a murderous puncher like Baer struggled to take out a one ankled Carnera, so I doubt Nino would. I’d say Primo overcomes some early adversity and bullies Nino
Primo jabs, uppercuts and clinches a decision. Valdez was a good hitter but I doubt he can rock Primo consistently enough to nulify him.
Carnera has a great track record against other giants and guys bigger than Valdes. Valdes was fighting in the smallest HW era after WW1. Valdes did beat his two tallest peers in Parker and Holman but those were other guys his size not Carneras. Of Carneras opponents bigger than Louis and Baer the only one Carnera struggled with was Godfrey who was better against giants than small guys. This was also earlier in Carneras career.