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