4x Jetson nano would cost $240, the Turing board will probably cost around $100 (it looks like they haven't decided yet) and you get 1,88 tflops; you can add 50 bucks and get GTX 1060 with 4.4 tflops and you can play games.
Not sure that's quite a fair comparison, because you'll need quite a bit more hardware to use the GTX 1060, and I think that the Turing board + Jetson setup would be all-inclusive (except a power supply and chassis, I suppose)?