Installing older version of Pytorch

Yes, there is PyTorch v1.0.0 pip wheel for JetPack 4.2/4.3 on this page:

https://forums.developer.nvidia.com/t/pytorch-for-jetson-nano-version-1-5-0-now-available/72048

Here are the links:

PyTorch v1.0.0 - JetPack 4.2 / 4.3