You need a thin 9mm socket but it doesn’t need to be special as such. I think the one I use is in a cheap shit Rolson set of sockets.
Getting the bushing out (the bit that has most likely worn as the Nano X seals don’t appear to be that great) puzzled me for a bit but a couple of drill bits did the job in the end. I think I used a 10.5mm pointy end down in a bit of wood and blunt end up in the pedal body which I then gave a few taps with a rubber mallet to get the bush out. Similar with a bigger, maybe 13mm, drill bit to get the new bush in. Not the right tools but did the job. The bushes alone are available online for about 50p each.
Be aware the Nano X has a different seal to the old Nano