My daughter has carried lip care products with her in her pocket since she was 5. She also keeps lip care products in her locker/cubby at school, in her backpack, and all the other places where she is often. We like Burt's Bees (which also has a colored stick, so she feels like she's using lipstick - we get the palest, most natural color), and some brand I can't think of right now - but it comes in a skinny, longer-than-chapstick, white tube.
You can also use Carmex a couple times - this would be sort of a negative incentive. Carmex is generally used for cold sores, so it works by peeling off the top layer of skin. The reason that I used to love it is that it tingles - and if your lips are really chapped it burns slightly. You feel like you're doing something! However, by getting that dead, cracked layer off, you are better prepared to start over. Once your lips are chapped, it's almost impossible to stop licking them - because they feel like they need moisturizer and the natural thing to do is to lick them, which makes them more chapped...
The best product out there for really chapped skin is made by Eucerin, called Aquaphor. Aquaphor is a mixture of petroleum jelly and lotion. My daughter's pediatrician recommended it to me as the best diaper rash cream available. We use it overnight, or sometimes first thing in the morning, for really chapped lips. It's fantastic.
In terms of dealing with the habit -
First, dealing with the chapped lips will help. Then, you could talk to the teacher and ask if she can carry a stress ball or something small in her pocket that she can unconsciously squeeze. Sometimes, just knowing that you have control over something and have something to do with your hands can help you deal with that little bit of nervous energy. Another option would be to send hard candy (you may be able to get away with this by sending non-medicated throat lozenges like "Hall's Breezes") with your daughter to school so that she can have something in her mouth to a) help her keep her tongue in her mouth and b) provide the oral stimulation that licking her lips may provide.
Talk to her teacher and let him/her know what your concerns are and ask for his/her advice. Tell her/him what some of your ideas are for helping your daughter and ask what her/his opinion is. As a teacher, I can tell you that we like to know what's going on, and that we really do want to help your child as much as we can. That includes helping her deal with any nervous energy and keeping them physically healthy. :)
Good luck!