You CANNOT use chunky or other pregeneration plugins to generate an iris world. You CAN use multiverse with an iris world as long as you create the world with iris first.

Let the server start once with iris before you try and create a world.​

• The server Should restart after first installation, if not restart Manually​

• /iris create <worldname> will create a world with the default overworld pack.

• Then set it as your default world should you want to​

• See more in our documentation