It’s not even been 24 hours since the Nexus 5 went live in the Play Store and it’s already been rooted. All credit goes to Chainfire for his awesome work with CF-Auto-Root.
All you need to do is boot your Nexus 5 into bootloader mode (turn off the Nexus 5 and VolUp+VolDown+Power). Once in bootloader/fastboot mode you need to connect it to your PC, Mac or Linux Box with a usb cable.

Then you need to execute one of the below commands based on what OS you are using on your laptop or desktop:-
– Windows:
— Run root-windows.bat
– Linux
— chmod +x root-linux.sh
— Run root-linux.sh
– Mac OS X
— chmod +x root-mac.sh
— Run root-mac.sh
Please note if the bootloader on your Nexus 5 is not unlocked this will wipe your data.
Download links and detailed instructions can be found here. Happy rooting the Nexus 5.