ABSTRACT.In this article, we focus on nano \( \mathcal{S} \)-closed sets and nano \( \mathcal{S}_{\delta} \)-closed sets are introduced and study. Also, we introduce and study nano \( \mathcal{S} \)-continuous functions and nano \( \mathcal{S}_{\delta} \)-continuous functions. Furthermore, we introduce the notions of nano topological spaces called nano \( \mathcal{S}\text{-}T_{1/2} \) space and nano \( \mathcal{S}\text{-}T_{5} \) space.