Student visas are temporary NON-immigration visas issued on the condition that foreign students return to their country of citizenship immediately upon completion or termination of full-time studies. There is NO way to change status from student to permanent resident, or even to an employment visa. You do your course & return straight home.
Intent to remain beyond the time-purpose of any temporary visa is visa fraud - grounds for visa denial or revocation & deportation with permanent bar to reentry. Since you intend to use a student visa to remain in NZ, you are not eligible for any student visa.