That's a bald faced hornet nest. They're large, easily angered, and there are usually guards hanging around the entrance. When wearing a bee suit, they'll cling onto the face screen and use their stingers to SQUIRT venom on your face. Around here, $250 is a bargain to get rid of one of those.
DO NOT hose it down with Raid. This "paper" nest is constructed to withstand the weather, and any amount of dousing the exterior will do nothing but piss off any hornets inside. They have a tiered umbrella like structure inside that will drain off liquids without harming them, so even spraying liquid straight into the entrance won't touch the upper tiers.
Within reach of a spray can, a pro would normally use Wasp Freeze or something better like that, but only to pause their inevitable attack long enough to cut it down and bag it. That high up, a Dust Stick with some Delta Dust would have it quiet in a day if you can find an exterminator who'll do that. Dust is your best bet here. Dust will drift up and all around the inside, reaching and poisoning the hornets in a way that no spray can.
The last one I removed, I put on a bee suit at night (when the workers have all returned home), put a floodlight on the ground, and kept emptying a can of Spectracide Pro directly into the entrance as they tried to exit and get me. Eventually when the opening was too clogged with dead workers for any more to escape (unless you hit them directly with the spray, even the best stuff doesn't work too quickly), I took the opportunity to cut it down and drop it into a trash bag. Foaming spray would have been better for this use...
The garbage can was still buzzing days later, so I held onto it for a few weeks before putting it to the curb. So yeah, even emptying an entire can of something considerably better than Raid straight inside didn't wipe it out!
The good news is it is high up. Wasps and hornets tend to fly maybe 10 or 15 feet straight out of their entrance in the direction of the sun (which is always upwards; at least a little). If they bump into you in that space, you WILL be stung, but since your nest is high up, you should be relatively safe at ground level unless you make loud noises (like run a lawnmower) that upset them.
The bad news is that your nest is attached to your structure and isn't just tanged in some branches you can cut. This is bad, because even if you clog the entrance at the bottom with dead hornets like I described above, you will inevitably open up the nest as you scrape it down, creating too many new escape routes to block. But if you could use a bellows duster to kill the occupants first, you could safely return some days later and cut it down.
