There are 46mm sockets on eBay, so they’re easy to find - just takes a couple of days to arrive. A lot of them are 3/4” drive though, so check carefully when ordering unless you’re equipped for working on tractors. :-)
Not sure how well equipped your garage is for tools, but that nut is pretty tight. I use a 24” breaker bar to crack it loose while the bike is on the side stand, that way you can lean against the bike and put lots of weight on the rear brake pedal without stressing the paddock stand.
BTW it’s 146Nm torque, for tightening it up again.