The power and toughness bonus granted to creatures by Nissa's last ability is determined only once, as that ability resolves
The effect is sadly not particularly useful, since changing the colour of a creature card doesn't matter that much to account for Shyft's poor stat-to-mana ratio
Other cards that become mainstays in his Deck include "Alligator Sword", "Swordsman of Landstar", and "Panther Warrior", and the Magic Cards "Scapegoat" and "Giant Trunade"
The second method, exchanging regular tickets, is instant and doesnt require additional resources
If you do, create a token that's a copy of that creature, except it's a Spirit in addition to its other types and it has "When this token leaves the battlefield, return the exiled card to its owner's graveyard." Whenever another nontoken creature you control dies, exile it
I personally stopped collecting Pokemon cards because my local retailers just gave up on trying to stock TCG items