Snapped Chain Doh !!

[Wookee]

Either using the new chain as above. Or, if you have enough slack in the old chain, get the rear wheel forward and then put the old chain back around the sprockets and overlap it. Then get something like a screwdriver that will fit through the links so it will just hold it while you crack the nut. If you make sure the overlap is on the bottom part of the chain there won't be too much pressure on your temporary join.