Nicol Bolas, the Deceiver

If Nicol Bolas's third ability causes each opponent to have 0 or less life, but it also causes you to try to draw more cards than you have in your library, the game ends in a draw.

While resolving Nicol Bolas's first ability, your opponent chooses a card to be discarded without revealing it, chooses a nonland permanent to be sacrificed, or chooses to do neither. Then that player discards that card, sacrifices that permanent, or loses 3 life. Your opponent can always choose to lose 3 life, even if they have cards to discard or nonland permanents to sacrifice.

If the target of Nicol Bolas's second ability becomes illegal, the ability doesn't resolve and you won't draw a card. If that target is legal but can't be destroyed, most likely because it has indestructible, you still draw a card.