Sometimes we have to be tough about stuff. It isn't good to have choc milk at bedtime but she clearly likes it; it's going to be up to you to make the change. She's going to yell and so on and you'll probably have a harder time at bedtime for a while, but then she'll get used to it. The teeth/health argument might help, combined with moving the drink to the table, pre-bed and teeth brushing, and then replace with water in bed if she's thirsty.
Do you have help at bed time?

Mine weaned from breast to nothing, so don't have specific experience, but we've all had to limit something that our kids would rather have all the time. I think the key is being prepared for the response and just pushing through till you're out the other side. Good luck!