With the update to X-Plane 12, the Cirrus Vision Jet SF50 has been fixed as the nose wheel should always have been set to a castor type. However, it can be a little tricky now to control whilst taxiing with the yaw axis on a joystick.
To re-enable nose wheel steering on the Vision Jet, or...
I've noticed a massive improvement in the visuals, such as the lighting, and better and stable framerates in this mega update from Laminar Research :)
https://www.x-plane.com/kb/x-plane-12-1-0-release-notes/
PS. If you're on Steam, make sure you verify the files once it has finished updating...