This study presents a mathematical model for investigating the critical buckling of circular cylindrical nanoshells containing static/dynamic nanofluids under the influence of different thermal fields that can also lead to the so-called hygrothermal field. To this end, classical Sanders theory of cylindrical plates and shells, which has been generalized utilizing the non-classical non-local theory, is used to derive the dynamic equations governing the nanofluid-nanostructure interaction (nano-FSI) problem. The resulting equations are written in dimensionless form and then analytically solved using Hamilton's principle approach. Herein, the applied heat and humidity fields are considered as three types of longitudinal, circumferential, and simultaneously longitudinal-circumferential forces fields. All of the above cases are examined separately for the two high-temperatures and room-temperatures modes. The results show a significant effect of nano-fluid passing through the nanostructure and its velocity and density rate on the critical buckling strain of the nano-system, especially at high-temperatures.