Bit of a mixed bag. I've not experienced any nausea, just occasional slight discomfort when racing bumpy tracks in a go kart but it quickly passes.
Some of my friends are fine with it too, some aren't. My girlfriend started to feel a bit sick after a few minutes, my neighbour instantly felt very sick.
Try plying with the g force and world movement settings. Set both to 0.0 and then move one up individually at a time by eg 0.2 each time and then have a try until you find what you are most comfortable with (which could be both at zero!).
G force simulates your head being chucked around by forces acting on your virtual body, too much of that can induce sickness since you aren't feeling those forces. I personally find I like just a slight amount of g-force induced movement to feel natural.
World movement is effectively horizon lock. At 0.00 the horizon will always stay level and the car will move around you so to speak. This sounds a little counter intuitive but it is actually closer to how your eyes and body work when actually driving. Next time you drive take note of how as the car bumps and moves around the horizon stays still while the steering wheel and dash move around in your vision.
Again for me personally I like a little in between. A little above zero feels most natural to me.
