You would need an Ubuntu18.04 PC, install NVIDIA SDKM and reflash your Jetson by JetPack.
See also First use of Jetson Nano doesnt boot - Jetson & Embedded Systems / Jetson Nano - NVIDIA Developer Forums
You would need an Ubuntu18.04 PC, install NVIDIA SDKM and reflash your Jetson by JetPack.
See also First use of Jetson Nano doesnt boot - Jetson & Embedded Systems / Jetson Nano - NVIDIA Developer Forums