What do you need a "one-click method" for the Nexus 5? The Nexus has to be the easiest device on the planet to root. Unlock the bootloader, install TWRP/CWM, flash the SuperSU binary. The hardest part is installing the SDK and drivers on your PC, which you have to do if you want to mod your device anyway, and even so it isn't that hard. Save a kitten.