Sore nipples are very common during breast feeding. One thing she can do is apply lanolin after she breasfeeds it will help with the soreness. The other thing she might consider doing is wearing a nipple guard. You can get them in the breast feeding section of the store.
First off she need to make sure she is nursing properly. That was my first mistake. She can call her Dr. or some hospitals offer a clinic to new moms that is free of charge. I used a prodcut called Lanolin (sp). It use to come in a purple tube.
Breastfeeding-grade lanolin is best for protecting blisters and chapped nipples. Apply it after every feeding. It is safe for babies and doesn't need to be removed. Acetaminophen is safe for Mom to take for the pain.
You should go the the local Walgreens or CVS and speak to the pharmacist. You can buy a cream over the counter to put on the tender area. I was given mine before I left the hospital with my son. Just make sure she wipes the cream off with a wet towel before feeding.