I mean shit, it's not even like CH is rich. Sure he could easily devise a scheme to get as rich if not richer then Batman in the 5 years, but people are ignoring that money and weapon wise, Batman definitely has the initial advantage.
And to add on to what Sanduser081 said, Batman has made a bunch of crazy shit with the amount of prep time he has. He can easily construct some godlike armor and hunt CH down. CH is still restricted by his knowledge of how things work, whereas Batman has technology CH knows jack shit about.
Now this isn't to say CH can't do the same, and in fact, he'll definitely make this extremely difficult for Batman, but in a war of technology, CH definitely loses. I mean you could argue CH could just create some new tech, but it's kinda NLF-y to do so since we have no idea how much advanced tech he'd be able to create and how advanced it'd be. You'd just be pulling stuff out of your ass at that rate.
I'm not voting yet, but it's either inconclusive, or Batman extremely high-diff.
But do you know who really loses? We do. Honestly imagine these two going at it and obliterating the Earth while they do it.
Guys, this is DCEU Bats. He's not building any Darkseid busting armors. His armors are 9-A at best and his weapons are Low 7-B at best. He's out skilled, out gunned thanks to nukes gases, and all kinds of guns, and he's vastly outsmarted.