Flexible and stretchable triboelectric nanogenerators (TENGs) are the next-generation systems for wearable and portable electronics. In this study, we have demonstrated an all nanofiber-based TENG for energy harvesting and biomechanical sensing applications. The TENG was prepared using the Forcespinning (FS) method to produce poly­(vinylidene fluoride) (PVDF) and thermoplastic polyurethane (TPU) nanofiber (NF) membranes. The TPU nanofiber membranes were interfaced with a homogeneously sputtered gold nanofilm. The experimental characterization of the PVDF-TPU/Au NF-TENG revealed that surface interfaced with dispersed gold in a TPU fiber membrane produced a maximum open-circuit voltage of 254 V and a short-circuit current of 86 μA output at a 240 bpm load frequency, which was, respectively, 112 and 87% greater than bare PVDF-TPU NF-based TENG. All systems were composed of an active contact surface area of 3.2 × 2.5 cm2. Furthermore, the TENG was able to light up 75 LEDs (1.5 V of each) by the hand-tapping motion. The resistive load and capacitor test results exemplified a TENG offering a simple and high-performance self-chargeable device. Furthermore, we have tested the TENG’s response for biomechanical movements at different frequencies, suggesting the TENG’s potential to be also used as a cost-effective self-powered flexible body motion sensor.