Nissa, Steward of Elements — ruling 1

If X is 0, Nissa enters the battlefield with no loyalty and is put into her owner's graveyard before you can activate her abilities.

Nissa, Steward of Elements — ruling 2

While resolving Nissa's second ability, if you can't or don't put the card onto the battlefield, it remains on top of your library.

Nissa, Steward of Elements — ruling 3

Once Nissa's second ability begins to resolve, no player may take actions until it's done. Notably, players can't try to change Nissa's loyalty once you look at the card or choose to put it onto the battlefield.

Nissa, Steward of Elements — ruling 4

If Nissa leaves the battlefield while her second ability is on the stack, use her last known loyalty to determine whether you may put the top card of your library onto the battlefield. If Nissa left the battlefield because she took enough damage to reduce her loyalty to 0, then her last known loyalty is 0.

Nissa, Steward of Elements — ruling 5

Nissa's last ability sets the base power and toughness of the lands to 5/5. Any +1/+1 or -1/-1 counters that were on those lands will apply to those values.

Nissa, Steward of Elements : règles, fonctionnement et interactions (MTG)

Nissa, Steward of Elements is one of those cards players keep asking about. Here is, in plain words, what its official text says, the rulings published by Wizards of the Coast, and the combos players actually run.

Official card text

+2: Scry 2. 0: Look at the top card of your library. If it's a land card or a creature card with mana value less than or equal to the number of loyalty counters on Nissa, you may put that card onto the battlefield. −6: Untap up to two target lands you control. They become 5/5 Elemental creatures with flying and haste until end of turn. They're still lands.

How it works : Nissa, Steward of Elements

Original English text — Wizards of the Coast / Scryfall

#1April 18, 2017· Wizards of the Coast
If X is 0, Nissa enters the battlefield with no loyalty and is put into her owner's graveyard before you can activate her abilities.
No other card is named in this ruling.
#2April 18, 2017· Wizards of the Coast
While resolving Nissa's second ability, if you can't or don't put the card onto the battlefield, it remains on top of your library.
No other card is named in this ruling.
#3April 18, 2017· Wizards of the Coast
Once Nissa's second ability begins to resolve, no player may take actions until it's done. Notably, players can't try to change Nissa's loyalty once you look at the card or choose to put it onto the battlefield.
No other card is named in this ruling.
#4April 18, 2017· Wizards of the Coast
If Nissa leaves the battlefield while her second ability is on the stack, use her last known loyalty to determine whether you may put the top card of your library onto the battlefield. If Nissa left the battlefield because she took enough damage to reduce her loyalty to 0, then her last known loyalty is 0.
No other card is named in this ruling.
#5April 18, 2017· Wizards of the Coast
Nissa's last ability sets the base power and toughness of the lands to 5/5. Any +1/+1 or -1/-1 counters that were on those lands will apply to those values.
No other card is named in this ruling.