The answer to your question can be found here. The basic idea is to set the option reduceXTicks to FALSE and also stagger the labels.
n1 <- nPlot(value ~ region, data = dat, group = 'variable', type = 'multiBarChart')n1$chart(reduceXTicks = FALSE)n1$xAxis(staggerLabels = TRUE)If the labels are big, you can control the size of the text using CSS. For now, you would have to manually insert this into your HTML, but in future version of rCharts, I will make it easy to add arbitrary HTML/CSS/JS to your chart, straight from the R console.
<style>svg text {font-size: 9px;}</style>