First find out if there is any work to be had as a Holistic Nurse before you invest time and money in that degree. I don't think there is. Any old nurse can practice Holistic Nursing without getting a degree in it, to the same extent as one could with that degree: not much. There's no money in it for the hospitals or the MD's, so there's no room for it in their systems, and nursing is not an independent profession that can prescribe treatments.
Don't get me wrong, I love the idea of holistic nursing, CAM, alternative medicine, mind-body-spirit integration in the healing model. There's just no living to be earned in it. I would love to take Barbara Brennan's course, but it's way pricey and there is no legal way to do the work afterward. A university near me offers a Bachelor's in Alternative Medicine; there's just no way that translates into a career. It's a useless degree. Even if you offer your services for free, the state licensing boards will go after you for practicing medicine without a license. It might take a while for them to notice you, but I wouldn't want to set up a practice with that fear hanging over my head.
Don't give up the idea of being a healer, just be very careful and thoughtful about what program you enroll in. Make sure you can actually DO the thing you're learning. It would be worthwhile to pay for legal advice before enrolling in one of these programs. A friend is in an acupuncture program, which is an independently licensed profession, although there are an awful lot of acupuncturists around here and I hope she can make enough to pay off her loans. I am pondering working toward a career as a Clinical Social Worker, which so far looks like a way to incorporate my calling into my career. But I can't see a way I can make as much money as I do now in nursing, so it's most likely my "retirement career", less physically taxing than nursing and, I hope, offering some psychic rewards I'm not getting from nursing.