A chip-in from an American nurse about studying here: It can be very expensive, especially for foreign students. The least-expensive schools are the state-supported ones. They add a large premium per credit hour for residents of other states, and many charge a premium above and beyond out-of-state tuition for international students. Private universities are immensely expensive, costing a year's income or more per year of study. There is financial aid available, but foreign students cannot qualify for many of the programmes.
Unless you plan to permanently reside in the US, it would probably be much more practical to obtain your training in the UK, then secure a travel assignment in the US for the cultural and professional experience if you would like.
As far as practicing here, there is no uniform national standard for nursing, and no national licence (at least at present, although this has been discussed before). Each state has its own board of nursing and nurse practice act governing scope of practice and standards of conduct. You must obtain a licence from each state you practice in at additional cost. Once you obtain your first US licence, most states have what is called licensure by endorsement (meaning that you can obtain a licence by submitting the application and fee and using your current licence as proof of practice and competency).
For information on licensure in California, here is the URL for the California Board of Nursing website:
The California website does say the following, confirming what someone said above:
If you have never passed the U.S. national licensing examination (NCLEX or SBTPE), you do not qualify for endorsement licensure. You must apply to take the examination instead.
This means that a UK licence does not directly qualify you for a California licence. You would have to take the licencing examination first. The exam is now given by computer rather than the two-day paper test that was used in the past.
You mentioned Los Angeles. You must also consider that LA is one of the most expensive cities in the US to live in. Rental costs are astronomical. Traffic is horrid (I visit the area every two months or so). If you definitely decide to study in the US, you may want to consider an area with a lower cost of living. Generally speaking, the midwest states offer a much more affordable lifestyle than the more populous coastal ones.
Ironically, I am considering taking an assignment in the UK for an extended period, and perhaps even permanent residence there.
If you want further information, I will gladly try to answer any questions you have.