Noland Lee only needed to find the right opportunity to draw Nicolette's soul into the crystal, and then use the Soul Shaping Tattoo on the crystal to turn her into an ethereal being.
As for what kind of ethereal being to turn Nicolette into, Noland Lee had already thought it through...
How about turning her into a "Spectral Ghost?" It was the most common type of ethereal being. Ghosts not only possessed the two features of "Immune Kinetic Damage" and "Constant Levitation," but they could also retain Nicolette's appearance, size, and mind.
If Noland Lee was less considerate, he could have turned Nicolette into a Vengeful Spirit or an Evil Spirit, since he had acquired the corresponding Soul Shaping Tattoo from the knowledge of "Soul Sculpting Magic" that he had obtained.
But just because he could do it, it didn't mean that Noland Lee would.
He spent some time carving the "Ghost Transformation Tattoo" onto the crystal.