The replacement of energy harvesters by flexible, bendable, and environmentally benign materials could result in a significant breakthrough in wearable and portable electronics. In this context, polymeric nanocomposites consisting of organic polymer and inorganic nanoparticles are considered as suitable candidates that demonstrate enhanced performance as compared to their unmodified pristine polymeric counterparts. Herein, lead-free Ba0.85Ca0.15Zr0.05Ti0.95(BCZT) nanoparticles were prepared by using the hydrothermal method and were impregnated within polymer matrix P(VDF-HFP) (poly(vinylidene fluoride-co-hexafluoropropylene) via electrospinning to enhance the electroactive beta-phase. XRD peak profile analysis and FTIR spectrum signify the strong emergence of electroactive beta-phase. The electrospun BCZT/P(VDF-HFP) nanofiber mat exhibits higher beta-phase fraction of 70.3% as compared to pristine electrospun P(VDF-HFP) nanofiber mat which can be ascribed to the presence of interfacial interactions at the interface of inorganic nanoparticle surface and the dipoles of P(VDF-HFP) inducing the electroactive beta-phase. The fabricated piezoelectric nanogenerator BCZT/P(VDF-HFP) exhibited an output voltage of 2.5 V which is much higher than that of pristine P(VDF-HFP) (1.0 V) due to in situ alignment of BCZT nanoparticles and higher beta-phase fraction.