Mamas, this girl needs some help!

My son will be 2 next month and he is nursing to fall asleep. No other feedings. Just to sleep. He has been exclusively breastfed, no bottles since about 4 months. He does use his sippy cup. But refuses it if there is milk in it. I don't want this to be an unpleasant experience for either of us really. But I'm very ready to not be nursing him to sleep anymore. Tips and tricks for an easy transition?