I would cut it a few inches at least from that nut, then use a connector that has shrink-tube, or just a connector and buy some shrink tube and heat it on over that. It's a red connector I think, but blue would work too.

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Sorry, just thought of the obvious! You need to get the nut out of the way in order to get the socket on. Got a good pair of wire snips?

This is what I would do to get the job done! Some might elect to another way so I'll just back off here and see what others might do differently........................