I have a friend who was just recently diagnosed with cancer. What would be something nice to give her?

Kindle. Depending on the type of cancer that she has she may be spending a lot of time at doctor's offices. She may really appreciate having something like a kindle to pass the time because she may be waiting a long time in waiting rooms and exam rooms.
Your Time. Offer yourself. Shopping, cooking, running errands are all time-consuming chores that can become burdensome to someone going throughout chemotherapy. Offer to drive them places or just to be with them during treatments or when having tests can be invaluable.
Yourself. You are the best gift. Your time. A kind word. Help getting to appointments. Be there when she gets out of surgery. Nobody really wants anything else except human warmth and help with basic needs.