Bugs of clade Hymenoptera (those nasty stinging insects), are very susceptible to soap. It causes them to suffocate. A power washer or even a car washing soap dispenser attachment on your hose can do a number on them.
Smoke passivates them, so if you can't get close to the nest, a smoke pot or other smoke making device will let you get near enough to do the job.
Also, there are some really fun videos on YouTube showing drones, home made flamethrowers, and shotgun shells taking down wasp nests.