For OSX 10.12, you will have to use Xcode 8.2 which comes with Apple LLVM 8.0.0. You can get it installed from https://developer.apple.com/.
Copy the XCode newer executable to the Applications folder. It will mostly create a version called Xcode copy.
Now download and install the Cuda Toolkit from the Nvidia website. You should find it here - https://developer.nvidia.com/cuda-toolkit.
sudo xcode-select -s /Applications/Xcode\ copy.app/Contents/Developer
The nvcc executable is installed in the /Developer/NVIDIA/CUDA-8.0/bin/. Add it to the path in the ~/.zshrc.
export PATH="/Developer/NVIDIA/CUDA-8.0/bin/:$PATH"
Run a source ~/.zshrc, and check if it works.
nvcc --version
Hope this worked!