Start applying for employment during your final semester of nursing school. Many hospitals start their application process months before the actual start date of employment, and by that time you will have graduated and hopefully passed NCLEX. For example, many hospitals new grad programs pop up on their websites for applications around october/november-ish, but the new grad program itself did not start unitl january or febuary. does that answer your question?
I applied 3 months before I graduated, when the hospital posted their new grad position. Call around and ask HR or a nursing recruiter if they have a new grad program and when they post the position online. DO NOT wait until you have your license as some hospitals pay for an NCLEX review course for you.