Content in biochem/upper division chem (including physical chem, which is nuclear chem) is much, much, much harder than nursing. Pre-med, pre-pharm, and any nonsocial sciences (i.e., pure sciences) tackle complicated concepts to grasp, hence, the demand for their knowledge is much higher, be it in medicine or in research.
The workload, dealing with the personalities, and other human factors, not content, are what make nursing a pain in my rear end. I've seen pretty much anyone who possess basic academic aptitude being able to plough through nursing programs of various kinds, and, of course, remain successful in what they do.
I still keep in touch with my science friends with whom I have tremendous camaraderie, and that's how I keep my sanity and my mind sharp, so to speak. I have a couple of close classmates in nursing, and I maintain my circle deliberately small in it for many personal reasons. For one thing, with a hard science background of two years+, you are able to explain the real "why's" of any bodily phenomenon when your nursing instructor may not be able to explain. Keep your textbooks. Knowing the biochemistry/mechanisms really does help in all molecular interactions.
'Nuff said from me.