“Is it right or against the law for a school nurse to call a student’s home and ask why they did not come to school that day?”
This is two questions. Let’s take the second one first: is it legal for a school nurse to call home to ask why you didn’t come to school? I am aware of no law that would forbid a school nurse from doing it, and indeed certain school board directives and regulations may require the nurse to do exactly that. At the same time, no one at your home is under any obligation to answer the phone, answer the nurse’s questions, or disclose anything about the student’s personal situation to anybody calling on the phone.
As for whether it’s “right” for the nurse to call? If you’re skipping school and hoping to get away with it, it may not seem “right”… but that never stopped Ferris Bueller.