Check out DIY Robocars and Donkey Car. They share a huge, helpful community on Discord (invite link). The members there will help you even if you aren't using a Donkey Car.

I was able to snag a Jetson Nano before the prices and stock went insane, but I struggled to get it running ROS at an adequate speed. I might have been doing it wrong, though!

Here's a link to my own, somewhat stagnant project: Robocar - TB05

Edit: the guy who started DIY Robocars, and who is very active on the Discord, was one of the people involved in creating Pixhawk and Ardupilot.