Nrwl has annouced that will support expo as an official plugin 🎉. As today all the development on this package stops and it will be considered deprecated.
You can find the alpha version of the Nx expo official plugin here. I encourage you to try it and give feedback to the Nrwl team. It will be so much better than this one.
I will follow the development of the new plugin closely 👀 and I'm going to upade this page with new info if it is needed.