I don't think the type of insurance you're offered will have anything to do with the job title of nurse or any level of certification you achieve.
It will all be a matter of what insurance company a facility offers. Every place of employment will pick their own insurance company and plan. Every employee, regardless of position/pay/experience, will be offered that plan. However, part-time employees can usually expect to pay more per paycheck for their benefits.
In my experience, the bigger employers (hospital versus independant Doc office), tend to have better benefits packages. Discount by bulk, you know.
When you interview for a potential job, they will ask you for any questions you might have. Be prepared to grill them on the healthcare benefits their facility offers.