Nico's Hyper is Miracle Walker. It allows Nico to effectively discard her current hand and draw hypers from any character, even those not in the match.
Miracle Walker is a very luck based Hyper, depending on chance to get a beneficial Hyper for the current situation. The best time to use it would be when the player has a full hand with >4 cards to get the most out of the conversion. The player should have in mind that Gift Hyper cards do not apply their effect thanks to Nico's passive, for examplewill not impede the player from playing other cards and will not give away cards for money; they will however allow Nico to gain more stars, so it's not a bad idea to keep them in hand.
This Hyper allows Nico to be very aggressive and scale up incredibly quickly with powerful effects and stats increase backing her up. Getting cards such aswill allow her to enter combat and have a higher chance to KO enemies, while others like let her come out of battles generally unscathed. Other supportive cards like can amass a great amount of stars or debuff and lower enemy players HPs safely like . Drawing multiple hypers can also easily trigger combos, such as activating then in Battle to guarantee a 10 roll.
The main downside of this hyper is its randomness. Despite the generally good cards that can be drawn and potential powerful combos, many times they won't be acquired in the appropriate situation or they won't be useful () or hinder Nico too much ( ). While it's possible to do it with less cards, it's generally better to get a full hand of cards before activating it to get more chances for a good card, which can slow down the activation on maps with panels too separated.