CUDA-only packages are stored in the cudaPackages packages set. This set includes the cudatoolkit, portions of the toolkit in separate derivations, cudnn, cutensor and nccl.

A package set is available for each CUDA version, so for example cudaPackages_11_6. Within each set is a matching version of the above listed packages. Additionally, other versions of the packages that are packaged and compatible are available as well. For example, there can be a cudaPackages.cudnn_8_3_2 package.

To use one or more CUDA packages in an expression, give the expression a cudaPackages parameter, and in case CUDA is optional

cudaSupport ? false
cudaPackages ? {}

When using callPackage, you can choose to pass in a different variant, e.g. when a different version of the toolkit suffices

mypkg = callPackage { cudaPackages = cudaPackages_11_5; }

If another version of say cudnn or cutensor is needed, you can override the package set to make it the default. This guarantees you get a consistent package set.

mypkg = let
  cudaPackages = cudaPackages_11_5.overrideScope' (final: prev {
    cudnn = prev.cudnn_8_3_2;
in callPackage { inherit cudaPackages; };