Ive seen it already compared to Winota as a powered down version, so there is probably a number of players who will be interested in this kind of effect
To shuffle cards in a stack, follow these steps: Deal all cards one card at a time into different piles randomly
Seven mana for a double Tutor
That's very synergetic with herself, and other manifested dread, morph and disguise stuff here
This effect benefits both you and them, so chances are, smart players will consider their options carefully, but with Nellys goading influence in play, you're often setting the board up so that opponents have no choice but to swing and draw you cards
The most important thing to remember is that while triggers create an ability on the stack which can be responded to separately from whatever triggered them, replacement effects alter how other effects resolve in real time