Heat gun. One of more powerful ones used for stripping paint, not the cruddy ones for heatshrinking. You need to get the nozzle hot enough to soften that clog to have any chance at all of clearing it, which means you're going to have to get it up to the kind of temperature you'd be printing at. Put the nozzle in a vise while you're doing this, so that you don't touch it and burn yourself, or drop it and set something on fire.

I have a sneaking suspicion you're going to have to chalk this one up to "lessons learned" and get a new nozzle, though.