Yep the big drive sprocket. Notice how its 'dished', by flipping it around the dish will be on the other side. and that should give you enough clearance.
Once that's done and 'if' you still need more. a couple thick washers on the axle inside of the dropout can give you a couple more mm's.
fyi- the bar its rubbing on is called the seat stay, and the lower one is called the chain stay eh.