What is a good way to handle tantrums about nursing?

My son is 15 months old, and I still feed him. Mostly at night, but before naps too. He doesn't need to feed to fall asleep, because if anyone else holds him and rocks him, he's out in less than 5 minutes. However, if I try to put him to sleep, he throws a tantrum until I allow him to feed. I sing to him, try a pacifier, rock him, walk him around, etc. It all continues until he nurses. And this wouldn't be a problem, except, he keeps nursing while he's sleeping. If I take my away, he wakes up and screams. If I try and switch it for a pacifier, he screams. I feel like a have no options. Any suggestions?