I am also trying to find a way to reverse tether through USB for my phone but it seems that there has to be built in drivers in the device that windows can use.. in my case my phone and your case the nexus...
If you connect to win7 pro or higher the prompt on your device should give you an option Internet Pass Through the same way it says .. charge only, transfer files .... if its not there then probably not..
If it is then you have to enable file/network sharing in your network settings on win7
That is what i have found so far...
Your other option is a USB Stick for $15
I am going with a WiFi Router i got refurbished from amazon for $3 more