A reliable car to get to and from work always makes a great gift! :chuckle
Seriously now...how about buying a tote bag made especially for nurses and filling it with nurse stuff: stethoscope, pens, little pouch with scissors - hemostats - flashlight in it; blood pressure cuff in it's own little bag, and a nice t-shirt for the nurse to unwind in after work.
There was a post on here..I think it was under 'PDA' or something...not too long ago, and they had some great ideas in ther that were posted to a husband looking to buy a present for his wife. Let me see if I can find it.