Riva on embedded Jetson NX

For getting Riva capabilities on Jetson NX,I followed documentation, to get riva - rmir from nemo model.
So,Nemo installation is first step to do. I am stuck at here. I have tried to install using docker image and by source. None of them worked.
Also, getting error while installing pip3 install nvidia-pyindex

Hardware - GPU : Jetson Xavier NX
Hardware - CPU : Jetson Xavier NX
Operating System : Jetpack 4.6