Right, much of the actual hard work in chip design would be outsourced. They pull in enormous amounts of templated chip design ("IP"), and clearly hired top talent to keep the whole thing going. They'd need simulators and labs for testing, but maybe outsource PCB layout. And I believe Elon even stated out loud that the fab itself is in Texas. Nobody makes chips on their own except perhaps Intel or Samsung. Even with all that industry support it's still a remarkable piece of work in a tight time line, but given the funding and the people, entirely reasonable.
> [Video] How can a company that has never designed a chip, design the best chip in the world?
They hire one of the best chip design teams in the world. Musk said this no fewer than two times during the presentation.