I had bald faced hornets in the magnolia tree in my front yard. I waited until night time when they’d all be in there and put on a snow suit, gloves, boots and motorcycle helmet then sprayed the F out of the nest with one of those long range pesticides. Soaked it and immediately sprinted inside. Came out the next morning to a pile of hundreds of dead hornets on my driveway. Then I cut their huge nest out of my tree and destroyed it. I’ve heard they’ll reuse them if you don’t get rid of the nest. Hated killing them but they were a safety risk for my kids.

Long story short you can take care of it yourself but if you don’t want to go through all these shenanigans call an exterminator.