I don’t see that there is a built in way to set the color of nested text based on the state of the button. As a solution, I am programmatically setting the text color based on button events, like so:
The problem with this method is that the text will always default to a grey color when the button is disabled. I tried dissociating the text from the button entirely by stacking them via an Overlay Palette, but the button in its disabled state still overrides the text color.