No, it is NOT the same thing as sea-sickness. I do not get sea sick, never have. I also don't get car sick if I'm a passenger reading a book or something. Never have. But turning, specifically TURNING, in VR, induces nausea.
When Oculus was first released (dev) games allowed for "free walking" FPS games which invoke a specific kind of nausea that is different from roller coaster style movement. It's the reason why almost all games are teleportation based now... Because this problem as I understand it affects the majority of people, even those who don't experience the other VR nausea which IS similar to sea sickness. This turning / angular momentum nausea does not attenuate with time. It's a huge problem with VR, and one which there is no solution for currently other than the poor "teleportion" movement mechanism.