Hi Joe,
Note that chart widget is intentionally simple so that it can be used for rapid sketching. I am afraid that making the chart adjustable would defeat this purpose, as there will be always more things that could be adjustable: values, labels, axes, legend, etc.
What you can do is create some custom components using existing widget types, like this is done in this stencil:
https://wireframesketcher.com/mockups/javafx.html
Let me know if this works for you.