Three is a particularly noteworthy casting cost for planeswalkers, historically.
Every single one of these has been a format staple; and it's not a strictly fair comparison, but Nissa, Vastwood Seer; Liliana, Heretical Healer; and Chandra, Fire of Kaladesh aren't exactly slouches either. Today, another three-cost planeswalker joins their illustrious ranks.
Getting to preview a new planeswalker is always awesome. Some have an obvious, natural home. Others demand a new deck be made to support them.
Sometimes, we get both.
When analyzing most planeswalkers, it can be a useful shortcut to view the three abilities as:
— Most powerful ability you can play when you cast the 'walker (usually the second ability).
— The ability you can use every turn (which typically adds loyalty as part of the “deal”).
— The ultimate, which typically has the “cost” of how many turns you have to plus without using the minus ability or taking damage.
I generally prefer to analyze the second ability first, since it is sort of like you're playing the 'walker as a “sorcery” that has an effect and then also gives you a planeswalker with a little loyalty. That perspective can give us a good idea of just how much we need out of the plus ability to justify the card. Once we understand the plus ability, we can evaluate the relative cost and risk of trying to use it enough times to ultimate.
Nissa's -2 ability reads:
-2: Put a +1/+1 counter on each creature you control.
So, right off top, Nissa, Voice of Zendikar is basically just better than Titania's Boon. You always have the option of dropping the 'walker, using the minus ability, and effectively getting a three-cost Titania's Boon and getting to keep a planeswalker pumping out tokens every turn.
Of course, Nissa, Voice of Zendikar is double green, and it's not like Titania's Boon was ever even remotely playable. Nevertheless, getting access to AOE +1/+1 counters at a better rate than usual is already something. Obviously, such an ability has a lot of appeal in a token-based strategy, but even just synergies with cards like Hardened Scales and Avatar of the Resolute are pretty attractive.
The +1 ability reads:
+1: Put a 0/1 green Plant token onto the battlefield.
This ability isn't that flashy, but it is strong. After all, even though a 0/1 isn't much to work with, it is a body, so it benefits from whatever anthem and pump effects you might be using. Nissa, Voice of Zendikar's +1/+1 counter ability works so well with the Plants, it's actually very appealing to make a Plant or two before using the minus ability (potentially even twice in a row). Even when not combined with pump effects, the Plants made by Nissa can serve as an “Icy” of sorts, holding off an attacker each turn.
Finally, we come to the -7 ability:
-7: You gain X life and draw X cards, where X is the number of lands you control.
A -7 means that we've got to make at least four Plants before firing off her ultimate, but if we can get to that spot, we're often going to be able to draw seven cards and gain seven life, which is most of Ugin's ultimate, when you think about it.
One of the most obvious homes for Nissa is in some sort of G/W tokens strategy. If we play Gideon, Ally of Zendikar, Nissa will put +1/+1 counters on all the tokens Gideon makes. Meanwhile, Gideon's emblem can make the Plants into bigger threats. They are also both great for helping to protect each other. Hangarback Walker, Secure the Wastes, Retreat to Emeria, and Monastery Mentor all play right into Nissa's gameplan, so we're not exactly short on good options.
One of the classic G/W tokens cards that has some tension with Nissa is the other Standard legal Nissa, Vastwood Seer. It's hard to know for sure if we can get away with both, but if it's close, there is added reason to potentially play fewer copies of one. Nissa, Voice of Zendikar is exactly the type of planeswalker that can sometimes just sit in play for several turns without dying or winning the game.
Sorin, Solemn Visitor, Abzan Ascendancy, and Catacomb Sifter all offer interesting elements if we splash black, to say nothing of added +1/+1 counter shenanigans. That said, we don't need to play white or black.
Dragon Fodder, Hordeling Outburst, and Atarka's Command could be used alongside Nissa, Voice of Zendikar to make some new R/G tokens deck. How much such a deck would look like a red aggro deck, how much it'd look like a R/G Landfall deck, and how much it'd look like something new remains to be seen.
One final style of application of Nissa is in some kind of a super friends deck, full of powerful planeswalkers. Not every planeswalker would be a natural fit alongside her; however, Standard happens to be particularly long on token-making and token-friendly planeswalkers at the moment. Gideon and Sorin are at the top of the list, of course, but even Ob Nixilis Reignited and Nissa, Vastwod Seer could fit in.
Even if we didn't go full-on planeswalker theme deck, we could just use Nissa, Voice of Zendikar in a control deck with a small token subtheme. If we're confident we're not getting run over by fliers, Nissa might be a passable “value play.” Sometimes, we could use it to reduce the clock, while other times, it's an alternative victory condition (when we believe drawing seven and gaining seven is functionally “victory”).
Whatever ends up being the best home for Nissa, Voice of Zendikar, make no mistake, this 'walker brings the noise!