Auratouched Mage enters the battlefield, searching your library for Nature's Chosen and attaching it to itself, then shuffling.
Activate Nature's Chosen's last ability by tapping Auratouched Mage, targeting Tawnos's Coffin.
In response, activate Tawnos's Coffin by paying ({3} magic symbol) and tapping it, exiling Auratouched Mage and all Auras attached to it and creating a delayed trigger ability.
Resolve the Nature's Chosen ability, untapping Tawnos's Coffin.
Resolve Tawnos's Coffin's delayed trigger from step 4, returning Auratouched Mage from exile to the battlefield tapped and returning all Auras exiled in step 4 to the battlefield attached to Auratouched Mage.
Auratouched Mage enters the battlefield, searching your library for Treachery and attaching it to itself.
Treachery enters the battlefield, untapping five lands.
Tap those lands to add at least ({4} magic symbol) .
Activate Nature's Chosen's first ability by paying ({0} magic symbol) , untapping Auratouched Mage.
Repeat from step 3, searching for the Aura of your choice in step 7 instead of Treachery.
Results
Infinite ETB.
Infinite LTB.
Infinite mana of colors your lands can produce.
Put all enchant creatures Auras in your library onto the battlefield.