As you draw closer to the mountains of Akoum, you can feel the land churn with the raw magic of the plane. This is the Roil--the manifestation of Zendikar's wild mana. Before you can react, you are caught up in it.
The Roil's deck has several evasive creatures, which is a problem for Nissa because for the most part her creatures cannot block them. The two Hitchclaw Recluses can block, but they aren't particularly effective against the bigger threats such as a Living Tsunami.
Since Nissa cannot block well, her plan needs to include attacking. As usual, Charging Rhinos are good because they can't be blocked by multiple creatures, so you can force chump blocks easily; the two Scute Mobs added to Nissa's deck are also quite useful since they'll be too large for the Roil to deal with after two or three of its triggers.
Gomazoa can be a problem since it can help the Roil deal with one of Nissa's threats that it wouldn't otherwise be able to deal with (particularly a large Scute Mob). If you can force it to chump block while it has summoning sickness, though, it can't use its ability. Note that Gomazoa's ability can be used outside of combat--doing so simply shuffles it into its owner's library; the opponent will do this if they run low on cards in their library or in response to an attempt to remove it using Wild Instincts.
There seems to be a bug with this mission that causes the game to crash at times, particularly when the AI starts their turn.