I can think of 2 things that could help:
1. Get someone else to handle bedtime. Tell your child that you "need" to do something (wash dishes, call grandma, take a shower, etc.), and that you will be in to tuck her into bed in a little while. If you wait long enough, she'll fall asleep with daddy (or whomever).
2. Don't wean, but cut the nursing session short. "You can nurse while I sing 'Row, row, row your boat'. As soon as the song is done, it's time to get into bed." Once the child is in bed, you can lie down with her and tell stories, or give a back rub, or sing songs. Those things will also help her transition to sleep.
Coolest thing my big girl said recently: "How can you tell the world is moving when you are standing on it?"
Coolest thing my little girl sang recently: "I love dat one-two pupples!"