I'm taking it to mean her text is literally going to change each turn to one of her different spells.
So on turn 1 it might say:
On Reveal: After you play your next card, destroy it and draw 2 cards.
Then on turn 2 she might say:
On Reveal: After you play your next card, add a copy of it to your hand
Then on turn 3 she might say:
On Reveal: After you play your next card, move it one location to the right.
So basically a random selection of one of the spells to make you decide if you want to Play Nico and use the spell that turn or wait for the one you need.