Activate Ashnod's Altar by sacrificing Autumn Willow, adding CC.
When Autumn Willow dies, Nim Deathmantle triggers, causing you to pay 4 to return Autumn Willow from your graveyard to the battlefield and attach Nim Deathmantle to it.
When Autumn Willow enters, it triggers, creating a creature token.
Activate Ashnod's Altar by sacrificing a creature token, adding CC.