Reseting the nether?

[butters.2647]

does anyone know how to delete the nether level data to get the new biomes in old chunks?

[Futhorka]

Fully exiting the game and deleting the [world]/dimensions/1 folder seems to do the trick. Just make sure you aren't in the nether or else it will give an error and won't enter the world. I'd backup the world.