Missing kernal image - Nvidia jetson nano

Hi, Im trying to build the kernal source as mentioned in this page : Kernal Customization
But Im getting this error, I tried with L4T version supported for jetson nano (jetpack 4.6.6 and older L4t ) eg, L4T R32.4.3.

Error message : Error: Missing kernel image /home/naveen/Downloads/Linux_for_Tegra/source/public/kernel_out/arch/arm64/boot/Image
This error occours after running $ ./nvbuild.sh -o $PWD/kernel_out

Thanks