There is no Yellow Nestor. Nestor will respond to lighting conditions with either more yellow and pink or more green. I have four of them in the ground in different locations and they all have unique color patterns.
There is a Yellow Nestor. I had it before the January 2010 freeze but is no more. The one above is the regular Nestor with the pink midrib showing up in the oldest leaves.
The yellow one grows much slower than the normal variety.