In this present investigation, we explored the impact of Sr2+ doping at the Bi-site on the structural, electrical, and optical characteristics of (NBT) nanomaterial. By employing the citrate auto-combustion method, we synthesized pure nano-perovskites, as well as various Sr-doped counterparts. Analysis of the observed X-ray diffraction patterns through Rietveld refinement revealed a rhombohedral phase with space group R3c, although the composition doped with 10% Sr exhibited impurity phases. The introduction of Sr2+ ions had a discernible influence on diverse microstructural parameters, including lattice parameters (a and c), microstrain, X-ray density, and particle size. Detailed morphological and elemental assessments were conducted utilizing TEM, FE-SEM, and EDX spectroscopy. The analysis of UV-Vis absorption spectra yielded a reduction in the optical band gap with increasing Sr addition up to 8% doping, followed by an increase. Random Free-Energy Barrier Model (RBM) was employed to analyze complex AC conductivity. The three-dimensional Godet's Variable Range Hopping (3D G-VRH) model was also applied to elucidate the electrical transport properties.