The way I got this was I used 2 controllers, loaded up Horde mode and picked Not So Pleasentville. The other maps work, but this one was far easier for me. Your characters will start next to the crane. When the zombies start coming toward you, activate the crane with R1. This will give you a ZKOTW nomination. The other controller I just let die. When you get the nomination, let yourself get killed as well. The game will save before going back to the main menu. Note, you only get a ZKOTW nomination when you are playing with someone else. Can not be done in solo play.
Repeat 11 more times. Takes about 15 minutes.