Yes, they are a term given for the same type of materials. Graphite nanoplatelets was suggested by a Carbon editorial, however, the term graphene nanoplatelet is more commonly utilized in the literature. The term graphene nanoplatelet is often more appropriate as it emphasizes that individual platelets consist of only 10-30 graphene layers. The term graphite nanoplatelet seems more appropriate for the thicker (100+ layer) platelets used in the literature.