The purpose of this article is to review most recent research on several kinds of generalized nano open sets in nano topological spaces, such as: nano α-open set, nano semi-open set, nano pre-open set, nano b-open set, nano β-open set and nano somewhere dense set, and then we investigate their implications and properties equipped with counter examples, in addition, we prove some of their related properties in special cases of approximations, and discuss where these class of sets become equivalent. Keywords: Approximation space, nano topological space and generalizations, interior and clousre in topologcial space. MSC (2010): Primary 54A05, Secondary 54D10, 54D15.