Guest WASPS NEST
You do not say how the nest is situated, but if it is in a hole in the tree i have used expanding foam with great success, If it is hanging from a branch i would dislodge it with a high pressure hose and then destroy the pesky thing making sure i had my running shoes on[Good luck]

If you can find the nest you can get a powder that you puff on the entrance the wasps take it into the byke and die. BUT we desperately need all pollinating insects live with them if you can.