I just tried and for some reason the $10 off coupon is not working online (at least on Board Games)...so it appears this is a B&M deal only.
The coupon code only works online if you change your payment method to Master Card before entering the code. The code is: "Y3T9A8E".
I put a few games in my cart and entered the code, and it DID stack with the B2G1. I haven't checked out yet, but I'm just confirming that it did work. My last three orders with Barnes & Noble have been canceled, though, so I'm not sure if I want to even bother.