I went to law school after obtaining my BSN and have been practicing law for 7 years now, so I wanted to share a few of my observations about the profession.
As other posters have said, make absolutely sure practicing law is what you really want to do. Also, evaluate how you want work itself to fit into your lifestyle. I was very fortunate after law school to get a great job practicing health law (not medical malpractice, but Medicare/Medicaid reimbursement, licensing, fraud investigation defense etc. for hospitals and health providers) making a six figure salary and I am still doing that practice full time today. I am one of those people that actually enjoyed law school and enjoys practicing law, BUT law, at least in my opinion, is an all consuming profession if you do it right. It isn't that lawyers that tend to be successful in practice are that much smarter than other lawyers, they usually just work harder (and by success, I don't necessarily mean money -- I mean lawyers that can get good outcomes for their clients). So, although I make a very nice salary, I easily work 60+ hour weeks, week after week after week. That wasn't so bad in my 20s, but now in my 30s, the time I devote to work starts to wear on me and my family. Being good at practicing law can really consume you and, at least in my experience, it is hard to find a way to provide more balance. I would certainly take a pay cut to work less, but that just isn't possible in a lot of practice areas. For most practices, it is an all or nothing thing.
Nursing, at least for me, provided a lot more balance. While shifts can be long and grueling, when they are over, they are over and you report to the next nurse and go home. You also have more control over how much you work. Believe me, when I think about 3 12 (or even 14) hour shifts a week, I long for those days sometimes.
One final thought -- the law is very competitive for a lot of practice areas. I was lucky that I got into a top tier law school, graduated in the top 10% of my class and was on law review. Those things make life after law school a lot easier. I wish I could say those achievements were all because of hard work, but frankly, although I worked very hard in law school, grades can be quite subjective and a lot of it is just luck and how you do, for most people, really dictates your career path.
Just wanted to share my thoughts and experiences with you for whatever they are worth -- both nursing and law are great professions.