Nano and NanoSD are literally the exact same thing, just SD has a industrial micro SD card already installed, whereas Nano requires you to buy a micro SD card to upgrade to NanoSD
I used a Belfryboy usb cable clone prior to my NanoSD, and I highly recommend it. He's quick about getting them shipped (considering it's from UK) and they are actually better than the Davis USB cables. The official Davis USB cable is USB 1.1 and you have to have a USB dock hooked to your TP-Link MB, whereas the Belfryboy clone is USB 2.0 and does not require a USB hub at all. The MB will still complain in the station tab about it, but it does function perfectly without the hub.
While technically you could update over the network with the MB, I would very highly caution against it since you could have a dropped package or lose connection and then risk bricking your console. Plug the USB cable into a computer to update your console directly. Firmware updates are very few and very far between, so you may not ever even need to anyway after an initial check for updates. Remember, the VP2 is a very old product, so most bugs have long since been fixed and I can't think of any I've seen or heard about yet.