+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, steward of elements, 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.