This code needs to be added to Javascript ChartModify event.
[size="4"]1. Displaying labels instead of values[/size]
chart.labels().textFormatter("{%x}");
[size="4"]2. Displaying value and percent of total[/size]
chart.labels().textFormatter("{%Value} ({%YPercentOfTotal}%)");
[size="4"]3. Displaying labels outside of Pie chart [/size]
chart.labels().position("outside");