as far as i know in the us,  rn is a full 4 year bachelor program.  before RN,  there is a LPN which does not require  yr degree.  as for getting a green card via work sponsorship, might need a 4 yr bachelor degree.  but this is not set in stone.  i am sure there are ways around to it.  may want to refer to US Immigration site.  They have category and the requirement.    

By the way, are you in the US already?