Share Android cell phone network connection over USB OTG to Wifi Android tablet
I would leave a comment but I dont have enough reputation.
I found this question and the first answer maybe shows a possible solution posted on xda.
For this you need root.

Download &amp; install a Terminal Emulator on your Android Tablet. Run the Emulator &amp; enter the following commands:
dhcpcd usb1
setprop net.dns1 8.8.8.8
The Android Phone from which net connection is to be sourced must be connected via USB Cable &amp; on that phone enable USB Tether.
Now you can access internet on your Android Tablet using your Android Phone as a USB Modem!

I always use Bluetooth to share internet between phone and tablet. A friend of mine has a Nexus 7 too and no problems with Bluetooth. Maybe you can look for a solution to this issues