@hjsvhsweb I haven’t done the Nexus 7 but if it’s anything like the Nexus 3 (which I believe it is) the charging/data board replacement should be very straightforward and involve no soldering. I’m guessing you already tried cleaning it out with air/99% iso?
If still not working I’d look on ebay or aliexpress to find the usb board replacement part. I’m guess it’s separate from the mainboard.
I recently fixed an Asus tablet (pins were mashed in beyond repair on the usb) and had to desolder the USB port from that board. It was a huge pain in the ass and also required a proprietary part. So…I’d avoid messing with solder on the port itself if possible unless you are going to chuck the thing otherwise and don’t want to buy a new charging board.
I also have a nexus 7 - really great tablet and worth fixing I say.
Is your Nexus 7 2nd generation? If so - here is a teardown. https://www.ifixit.com/Teardown/Nexus+7+2nd+Generation+Teardown/16072
And…here’s a board replacement https://www.youtube.com/watch?v=oKMMYiVQTrY
I haven’t looked at the teardown but another option might be to reflow the board in the SMD oven at VHS or try a heat gun (unless the pins are mashed in cause then you are looking at a board/port replacement for sure)