Download HICharts.zip file and extact it. You will get HICharts.js file. Replace this file on the above location “…\hi\apache-tomcat-9\webapps\hi-ee\js\vendors” (before replacing do take a backup of the file present here).
After that in the open the card in edit mode, and put this below code at the JSeditor
var widgetText = $("#widget-value").innerHTML
widgetText = widgetText.replace(/(\d)(?=(\d\d)+\d$)/g,"$1,");
$("#widget-value").innerHTML = widgetText
Note : Above code is must to insert in JS Editor at report level and there are no UI driven customization script applied.