Functionalization of nanomaterials is widely utilized in the design of sensing layer of gas sensors, whose high sensing performances largely depend on the design of the materials component and structure. Here, an advanced 1D hierarchical nanofibers consisting of 1D backbone with well‐defined p‐type NiO nanosheets built porous shells is reported. The backbone is filled with SnO₂ and ZnO nanoparticles to form a 1D heterostructure nanofiber that enables accelerated reaction rate between target gas and sensing layer. In the outer nanosheets shell of 1D hybrid nanofiber, NiO is a p‐type semiconductor with high catalytic activity to create extra rich heterocatalytic reactions active site within interface layers. Importantly, the NiO nanosheets shell exhibit a highly porous but robust architecture that could enhance the utilization ratio of the sensing layer upon target gases. Taken together, these results highlight the merits of employing novel functionalized SnO₂–ZnO nanofiber as active components to achieve a high sensitivity of 12.2, excellent selectivity to formaldehyde at a low temperature range of 120–150 °C, which are superior over the SnO₂ nanofiber, SnO₂–ZnO nanofiber, and NiO nanosheets.