Nahiri, the Harbinger

[+2]: You may discard a card. If you do, draw a card.
[−2]: Exile target enchantment, tapped artifact, or tapped creature.
[−8]: Search your library for an artifact or creature card, put it onto the battlefield, then shuffle. It gains haste. Return it to your hand at the beginning of the next end step.

Commander Masters

+2: You may discard a card. If you do, draw a card.
−2: Exile target enchantment, tapped artifact, or tapped creature.
−8: Search your library for an artifact or creature card, put it onto the battlefield, then shuffle. It gains haste. Return it to your hand at the beginning of the next end step.

Shadows over Innistrad Remastered

Commander 2020

+2: You may discard a card. If you do, draw a card.
−2: Exile target enchantment, tapped artifact, or tapped creature.
−8: Search your library for an artifact or creature card, put it onto the battlefield, then shuffle your library. It gains haste. Return it to your hand at the beginning of the next end step.

Mythic Edition

Shadows over Innistrad Promos

If the artifact or creature put onto the battlefield with Nahiri’s third ability leaves the battlefield before the next end step, it won’t be returned to your hand from its new zone.

If you find a noncreature artifact with Nahiri’s third ability, it will still gain haste, even though it won’t be meaningful unless that artifact becomes a creature.

You can activate Nahiri’s first ability with no intention of discarding a card just to add loyalty to Nahiri.