Nemata, Primeval Warden

Reach
If a creature an opponent controls would die, exile it instead. When you do, create a 1/1 green Saproling creature token.
{G}, Sacrifice a Saproling: Nemata gets +2/+2 until end of turn.
{1}{B}, Sacrifice two Saprolings: Draw a card.

Dominaria United

Reach
If a creature an opponent controls would die, exile it instead. When you do, create a 1/1 green Saproling creature token.
{G}, Sacrifice a Saproling: Nemata, Primeval Warden gets +2/+2 until end of turn.
{1}{B}, Sacrifice two Saprolings: Draw a card.

Dominaria United Promos

If a creature an opponent controls would die, and both Nemata and another effect are trying to exile it instead, that opponent chooses which effect to apply. If Nemata's effect ends up not applying because of this choice, the triggered ability that creates a Saproling token won't trigger, even if the creature card ends up in exile.