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