Dead Rising 2: Off The Record

HUGE SPOILERS AHEAD!

The other guide's exploit works plenty well but for those who may want to win this boss fight not using exploits, I highly recommend that you arm yourself with a sniper rifle. If you go to Palisades Mall there is a gun shop on the second floor near the escalators. Also there are bathrooms on the second floor of Palisades Mall so go pick up your guns, save the game, then head back out and fight Chuck.

To easily get to Palisades Mall (especially if you're a lower level and don't have a lot of health or inventory space), from the safehouse, walk out the doors from Royal Flush Plaza (use the doors near the convertible and slot machines). From there, go across the street and walk inside the Atlantica Casino and follow the signs to find Palisades Mall. The entrance to Palisades from Atlantica is right by the escalators that you need to get to the second floor-- once you're on the second floor, turn right from the escalators and the gun shop will be one of the shops on the left. 100% of the time there are looters in the gun shop so be prepared to defend yourself from 1-3 looters.

I recommend that you pick up at least 2 sniper rifles, 3 if you have bad aim. Once you have the rifles, go save the game in the bathrooms on the same floor, then take the escalators down, exit through Atlantica Casino, then head back out to the strip. If the Chuck fight has already been triggered, he will likely be coming right for you, so make a beeline from the exit of Atlantica to the fenced in fountain area in the middle of the strip. Get inside the fenced in area-- this will keep you safe from both Chuck and the zombies in the area. Get out that sniper and wait for Chuck. He will ride back and forth and will come to almost a full stop when he is turning the bike around, which is your chance to shoot him. I was able to take him out in around 5 minutes and I used one of the sniper rifles completely and about half of the second sniper rifle (I also missed somewhere between 5-10 shots).