What does "cell range" mean?
I'm Pretty sure its the Length of the nest, extending the range of how many cells you can put on a floor
It's not length of nest, its the area of effect for some cells. Some cells have a limited range of effect, and that increases them.
It means how far your cell effects reach. Example, a Transfer cell might be able to carry a captive up to 4 cells away. Increase your Cell Range and now Transfers can carry them 5 cells away.