I have a hidden search that outputs a table with username information in the field UserName. Using $results[0].UserName$ I can display this information using Sideview Utils HTML module.
How can I pass the $results[0].UserName$ to other parts of my XML, like a HiddenChartFormatter that creates a pie chart?
You should look at the ResultsValueSetter module.
ResultsValueSetter is the "bigger hammer" to the HTML's $results[0].userName$ feature, since with ResultsValueSetter you end up with a simple $userName$ token that you can use in any module downstream of the ResultsValueSetter.
As always, Sideview docs has a whole page of docs and working examples for the ResultsValueSetter. Actually in latest Sideview Utils (2.4.8), there is a section for the 3 related modules - ValueSetter, ResultsValueSetter and ArrayValueSetter. They are somewhat advanced modules, but in dashboards that have moderate to advanced complexity they are important tools to know about.
Got it working with ResultsValueSetter.
Cheers!