Woodley fought Wonderboy for a fucking HOUR and landed that overhand right a grand total of 3x. Each time being late in the fight.
Wonderboy also has bad boxing defense and has proven to be susceptible to big right hands.
What makes you think he would land it on Nate that fast?
Wonderboy was probably the toughest stylistic match-up for Woodley, he's a huge WW, has great outside movement/timing. As noted he doesn't have the best defensive boxing, but he does have some nice counters and obviously a solid chin (since he somehow didn't die from Woodley overhands). His whole gameplan against Woodley was to outfight and turn it into a point-karate type contest where he could negate the wrestling and power by staying on the outside to use his kicks and not brawling/clinching. Being able to repeatedly land killshot overhand rights against very talented strikers like WB shouldn't be dismissed so easily.
Don't remember WB eating too many overhands specifically outside of the Woodley fights, best punch Masvidal landed on him was a left hook. For the most part seems like guys haven't been able to figure out how to close the distance without eating shots and then chasing ghosts, so he hasn't taken much damage before the Woodley fights since like Matt Brown?
I actually counted 5 x Right Overhands from Woodley that dropped him a total of 5 times (3 in the first fight, 2 in the second fight); he did that against one of the best overall strikers in the division and has a very tricky style that negates some of his strengths. He also knocked out Robbie Lawler in 2 minutes when he was supposedly unstoppable. He outstruck Carlos Condit and destroyed his leg. So he's been pretty consistent in out-striking the best strikers they can match-up against him.
Stylistically it's just a bad match-up for Nate, he's pretty far outside his prime and not fighting regularly, taken a lot of damage in the last couple fights he was in (and a ton over the course of his career). Woodley probably is on the decline but still such an athletic beast, so will definitely have a big speed/strength advantage, hasn't been in too many wars outside of the Marquardt fight back in the day. Diaz theoretically would have the cardio advantage if he can dictate the type of the fight it is (boxing out-fighting game). However, Nate's sub-par kicks/plodding footwork/lack of TDD will be up against one of the most athletic and powerful wrestlers in the sport so it's a pretty glaring weakness to be exploited by a super intelligent fighter/camp that he would be up against.
Woodley used to base his game around that fake blast double/overhand right set-up a lot, Nate is a slow starter and if you bait him into exchanging early he typically is there to be hit. Nate is tough as nails but if he was getting repeatedly dropped by shots from Conor the same shots from Woodley will put him away. Woodley has the same ability to close distance quickly as Conor while being more explosive and having the double-threat of the takedown.
I just think Woodley is a very intelligent fighter that will be able to exploit the openings with his skillset - maybe he doesn't KO Nate that fast, who knows...but I wouldn't be surprised at all if it was first round or even in the first big exchange.