The codes are described as follows:
170 - Nursery, General Classification
171 - Nursery, Newborn, Level I
172 - Nursery, Newborn, Level II
173 - Nursery, Newborn, Level III
174 - Nursery, Newborn, Level IV
It isn't broken down by Nursery or NICU. It depends on what level your facility considers regular nursery care and what is NICU.
Hope that helps
Michele