Hi MikeS ,
There are two ways you can go about making this happen, depending on what you want it to specifically look like you can test them out and see which one gives you the right formatting and what you want.
(1) You can normalize the chart, which is an option you'll find when editing the widget close to the bottom of all of the options available on the simple chart widget.
(2) You can change the metric options to display this. You'll click on your metric, and from there you'll change it to a percentage under the "source" part of metrics, and then you'll have to go to "options" tab of metrics and you can select different options under "show value as", they'll have different ways to calculate the percentage (I.e., out of grand total, column total, etc.) - this one lets you really decide which option of calculating percentages you want.
Here's a link to a qualtrics support page that also lays out how to do these different options - I typically use normalize chart and it gives me what I want, but just in case it isn't exactly what you're looking for, the other options are there!
Simple Chart Widget (CX) - Qualtrics Support

Thank you so much! Such an easy solution!