There are three areas: Verbal, Math, and Science. Before I took it, the Nursing Coordinator at my school said the questions are designed for pre-nursing students, meaning you need no knowledge of nursing. However, they are phrased in a way that makes them pertain to medicine. For instance, one of the math questions asked me to figure ccs or mls. Another was a word problem involving an IV drip or something. Again, they were math, but termed so that they pertained to medicine so to speak.
I remember some molarity, basic chemistry (which I have never even had, lol) and some astronomy in the science part. Those were all questions that stood out to me b/c I didn't know anything about those subjects. Oh and some physics too.
As for the verbal, I don't even know. I did the best on that part b/c I always do well on verbal. Don't remember it being difficult at all. I've heard others say they did the worst on verbal b/c they always do poorly on verbal, lol.
All in all, to sum it up. I quit highschool during the 11th grade. I had had only elem algebra in college at the point of taking the NLN, no biology (ever), no chemistry (ever), no physics (ever), and I did not study. I made a composite of 130.
If you check out the NLN website there are some sample questions. My cousin used the NLN study book. She said that it helped her ALOT, especially if you are worried about how the questions will be termed. She made a far lower score than me inspite of her studying and prior A&P courses, etc. She is smart, just a bad test taker. So you see there are multiple factors that will play a role in how well you do.
Hope this helps. Good luck. I'm sure you will do fine.