I was messing around in Creative and giving myself random effects, I gave myself nausea and flew through a nether portal with an elytra. The nether portal had already been placed and I had already built stuff by that nether portal. But when I went through another portal had spawned me in the nether. The cords in the nether were almost the same as the ones in Overworld. My nether portal coords in the over world were -653 640 and the nether portal spawned me at -644 680. But my previous portal had been at 10, 30. Not sure why but when i walked through the portal with nausea nothing happened. It only worked when i flew through with an elytra.