I bit my nails till I was 8. My favorite aunt made a comment about how she had always wanted long nails and was not able to grow them. She said she admired my moms nails and thought it was a shame that I bit mine, cause she (my aunt) would love to give me a pedicure and paint them a pretty pink.That did it for me. I quit and then 2 weeks later, I was able to call my aunt and ask if she thought my nails were long enough. She was so excited she picked me up, did my nails and we went to a nice lunch, just the 2 of us. I was thrilled. we had never been anywhere just the 2 of us. So maybe think of a special treat that your daughter would enjoy as a reward for not biting her nails.
For your 2 month old, you may want to consider wetting baby wash cloths and then freezing them. Then give them to your baby to chew on. We did this for our daughter and it worked great.