Yeah, I've successfully runned ArchLinux on JetsonNano (both P3448-0000 and P3448-0002). It doesn't make any specific challenge to do it. You have just to download L4T (https://developer.nvidia.com/embedded/l4t/r32_release_v5.1/r32_release_v5.1/t210/jetson-210_linux_r32.5.1_aarch64.tbz2), and unpack basic ArchLinux rootfs archive to rootfs dir (but not forget to remove basic Archlinux kernel file - /boot/Image). And it's ready to be flashed onto Jetson Nano. Then, first booted, it can be updated and customized.