Molds don't "feed" yeast necessarily like sugars do, but they can trigger further immune responses in an already candida-weakened body, the microscopic spores travel through the air and when a person already has a yeast infection, these spores just add insult to injury when it comes to immunity.
Moldy foods are not a good idea period, whether you have a yeast infection or not. For example, many people in developing countries die from aflatoxin - http://en.wikipedia.org/wiki/Aflatoxin
This is a mycotoxin (a poison produced by a fungus) in this case - Aspergillus. Your guess is as good as mine as to what toxins you will be consuming with mold pistachios. Throw them out and get fresh pistachios, why risk potential liver cancer tomorrow because you decided to eat moldy nuts today.
There are potentially thousands of different molds and fungi, but probably the Darth Vader of them all is Stachybotrys, often known as “black mold”, you will find this black demon in bathrooms where there are plumbing leaks, or in houses with a leaky roof, etc.
The point is, molds don't "feed" candida, but create additional immune problems you can do without when you have a yeast infection.