Nexus 5 touch response is slow while charging
[Moving from comments to answer]

This could be an issue with either debugging mode switched on or the power source itself!

Please try on AC Power, this is a known issue with quite a few phones! In fact I had this issue with my N7000 running CM10, the phone is just lying around now. Just to be sure, is USB debugging off ? Just to see if that is the issue for me, I tried different sockets at home with my old phone! It varies based on the power supply. All I can say is stop charging through these faulty places