My state requires the NHIE.
I also took the $50 pretest test.
It was a waste of money IMHO.
I lurked here at NACHI for a while and took the NACHI test several times as preparation for sitting for the NHIE.
When I could take the test and get above 90 with ease I took the NHIE and passed with no problem.
There is a wealth of information on this site and depending on your background and training it will serve you well in preparation.
If you identify some weak areas in your knowledge, avail yourself of the free and paid training available on this site.
Good luck and don’t be afraid to ask questions.
You will find most the members here to be very helpful.