Search your library and graveyard for a card named Forest, a card named Brambleweft Behemoth, and a card named Nissa, Genesis Mage. Reveal those cards, put them into your hand, then shuffle your library.
You can find any or all of the cards listed with Nissaâ€™s Encouragement. You could even find none, but that wouldnâ€™t be very encouraging.
Nissaâ€™s Encouragement canâ€™t be used to find a card with the land type Forest that isnâ€™t also named Forest (such as Sheltered Thicket from the Amonkhet set).