From the moment Nissa, Voice of Zendikar was spoiled I have been adamant about the fact that it's probably one of the best, if not the best card in the set. Unsurprisingly, with the full spoiler up this still appears to be true. Nissa plays entirely too well with the best card from Battle for Zendikar.
There are a lot of interesting tools to flesh out a deck with these two powerful planeswalkers, and I imagine it will take some time to polish the best list. My gut tells me that I want to curd Dragon Fodder into Nissa into Gideon to maximize the potential power of these anthem effects. In another unsurprising turn of events, I'm quite confident that Oath of both Nissa and Gideon will fit well into this deck.
Making sure that we're able to block for Gideon and Nissa seems very important, and I like borrowing Elvish Visionary and Hangarback Walker from Sam Black's token deck. Wingmate Roc will help us glean more value from all of our little creatures, and I'm curious to try the new Chandra to get a feel for it.
This is the initial list that I would start testing:
Virulent Plague poses some serious problems for this deck. In the maindeck you have the ability to inevitably get enough Gideon emblems to get around it, but there should probably something in the sideboard that deals with Plague a bit more efficiently. Outside of that weakness, this deck seems quite robust and powerful, and I imagine something similar will shortly become a pillar of Standard, though it's unclear exactly what will be presented to supplement Gideon, Nissa and their Oaths.