Activate Ashnod's Altar by sacrificing Nevinyrral, adding CC.
When Nevinyrral dies, its second ability and Nim Deathmantle trigger.
Resolve the Nevinyrral trigger, choosing not to pay.
Resolve the Nim Deathmantle trigger, causing you to pay 4 to return Nevinyrral to the battlefield from your graveyard, and attach Nim Deathmantle to it.
When Nevinyrral enters the battlefield, its first ability triggers, creating a tapped 2/2 Zombie creature token for each creature that has died this turn.
Activate Ashnod's Altar by sacrificing a Zombie token, adding CC.