I get it to work as an MTP, but thats not what I want.No. I haven't tried plugging it into a PC yet. But, as I understand it, the N5 cannot be used as a normal mass storage device. Plugging it into a PC connects it as an MTP (Media Transfer Protocol) device. To make this work an MTP driver must be installed.
To get the driver you will likely have to download the latest Android SDK.