Hello NackNack. “Rendering Device has been lost” is Overwatch’s standard error message when your graphics card shuts down while the game is in operation. There can be a wide variety of issues that can cause this but since you are using a standard GTX 1060 graphics card I need you to start with these troubleshooting steps first:
Since you are using a RTX 20X0 series graphics card, you will have a specific known issue that NVidia has been investigating and trying to resolve. However there is a temporary work around solution for RTX users which you can find out about here:
As a reminder, this troubleshooting step is only for users with the RTX series of graphics card and will not work for those with NVidia GTX or any AMD graphics card.