Adding hover tooltip for "NaN" values in choropleth

How do I add hover tooltips for values that are “NaN” in choropleths? Is there a way to change the color of “NaN” states to gray?


We don’t render locations with NaN values and in turn that they don’t get hover labels.

I would suggest splitting your data arrays into two traces, one with non-NaNs values and one showing the NaN using some dummy value: