You'd have to favor Chocolatito based on skill and class, but Romero has a legit puncher's chance. He was a truly devastating puncher at 112-115, and Chocolatito's chin isn't as good as Tapia's. Still, on class alone Choco is the safer pick.
Romero has a better chance at 115 than he does at 112. At flyweight, I admit Chocolatito has a rather huge edge. At super fly, Romero's a live underdog.
If Choco can navigate around that power, he walks away with it. I don't think Choc has enough of a track record of losing to punchers to lose against Romero.