Not sure if JH moves different, but I'm state employed and a non-exempt employee. The status relates to your FLSA employment status. From my experience:

Exempt means you are exempt from the Fair Labor and Standards act and don't get paid overtime. Instead, you are eligible to get comp time. Generally paid a fixed salary.

Non-exempt means you are eligible to get paid overtime if you work more than 80 hours in your pay period. Generally paid by the hour.

So if your offer says you are exempt from overtime, it means you won't get time and a half if you work more hours than youre supposed to. You'll just earn bankable time off in the future. Usually certain positions are exempt and non-exempt. For example. Most higher up positions will be exempt because they don't get paid hourly. More administrative/clerical jobs are non-exempt because they get paid by the hour and aren't required to work more than their standard 40 hours a week. It would make sense that a nurse position would be exempt because its pretty common that you all will work more than 40 hours a week, thus costing the hospital a ton of money in overtime costs.