Activate Skirge Familiar by discarding Nightmare Void, adding {B}.
Bone Miser's third ability triggers, causing you to mill two cards and return Nightmare Void from your graveyard to your hand.
Repeat.

Infinite self-mill

Near-infinite black mana

Near-infinite self-discard triggers

Bone Miser

Nightmare Void

Skirge Familiar

Attempt to draw a card. The draw will be replaced by Chains of Mephistopheles, causing you to instead discard Nightmare Void. Then, you will mill two cards and return Nightmare Void from your graveyard to your hand due to Nightmare Void's dredge ability.
Bone Miser's third ability triggers, attempting to have you draw a card. The draw will be replaced by Chains of Mephistopheles, causing you to instead discard Nightmare Void. Then, you will mill two cards and return Nightmare Void from your graveyard to your hand due to Nightmare Void's dredge ability.
Repeat step 2.

Combos with "Nightmare Void"