As of the time of this writing, Google does not provide a USB driver (for Windows) for the Nexus 5. The usual link (http://developer.android.com/sdk/win-usb.html) shows Wind
I found a solution in How I fixed the MTP issues on Nexus 7.
Another way of fixing this on Windows 8: This problem may happen, because you have the Google ADB driver from the Android SDK installed. Windows will pick the ADB driver over the MTP driver, even when USB debugging is turned off on the Nexus 7. It also comes back when you upgrade from Windows 8 to Windows 8.1. To fix this:
It was confirmed working with the Nexus 7 2013 as well.