I don't understand why I keep getting the "Not used within component" error

Thanks everyone,

Here is my setup visual.

I wish to set up this component with 3 properties. I can successfully set up 2, but the third continues to not work. The problem property is the icon/light-forest layer. I want that to be another Nested instance, just like the hex-color layer. Every time I try, I get the “Not used within component” error, and it doesn’t show up as a Nested instance when I try to link it. I don’t understand what I’m doing incorrectly.

-Chris