I do not have personal experience with this. But two friends of mine (CNMs) have been in NHSC programs for loan repayment.
One was awarded a scholarship during graduate school - so I believe her tuition was paid in exchange for her agreeing to move after graduation to where she was needed and working for 2-2 1/2 years or so.
The second friend had taken out loans for her Master's degree and started working as a CNM at a site that was an NHSC approved loan repayment site. She applied for loan repayment - I think she has to re-apply each year, maybe every two years - and in exchange for her agreeing to stay at her current position for a year (or two) - significant portions of her student loan debt are paid off (thinking $35K-$50 per year). I think the first year/first payment is the largest, then the following years are lower payments. And the payment amounts change each year - and it is possible for the site to be removed from the approved site list, too. That hasn't happened in her case.
NHSC is one of the faster ways to pay of student loan debt - especially since a Master's degree CNM program can easily top $100K - especially at private universities.
The scholarship requires that you agree to go where you are needed after graduation and some students don't have that flexibility or desire to be uprooted to some place else for 2-3 years. I've have known some students get the NHSC scholarship and turn it down for that reason.
The drawback is working at a site that is not where you'd want to be. But for the money - in loan repayment - it's usually worth it.