JSFiddle - React, Tailwind, and code Playground

HTML

<link rel="stylesheet" href="http://cdnjs.cloudflare.com/ajax/libs/nvd3/1.0.0-beta/nv.d3.css">
<script src="//cdnjs.cloudflare.com/ajax/libs/d3/3.4.9/d3.js"></script>
<script src="//cdnjs.cloudflare.com/ajax/libs/nvd3/1.1.15-beta/nv.d3.min.js"></script>
<div id="chart">
   <svg></svg>
</div>

CSS

#chart svg {
  height: 400px;
}

JavaScript

var margin = {top: 50, right: 50, bottom: 120, left: 70};
var svg = "#chart svg";
var normalisedData = [{"key":"Data 1","type":"bar","yAxis":1,"values":[{"x":0,"y":6500},{"x":1,"y":8600},{"x":2,"y":17200},{"x":3,"y":15597},{"x":4,"y":8600},{"x":5,"y":814}]},{"key":"Data 2","type":"line","yAxis":2,"values":[{"x":0,"y":2},{"x":1,"y":2},{"x":2,"y":4},{"x":3,"y":6},{"x":4,"y":2},{"x":5,"y":5}]}];

var axisKeys = ["2014-Jan","2014-Feb","2014-Mar","2014-Apr","2014-May","2014-Jun"];

nv.addGraph(function() {
    var chart = nv.models.multiChart()
        .options({reduceXTicks:false})
        .margin(margin)
        .color(d3.scale.category10().range())
    ;
    
    chart.xAxis
        .tickFormat(function(d){
            // If there is such element, return it
            if(typeof axisKeys[d] !== "undefined"){
                return axisKeys[d];
            }
            return "";
        });
    
    // Get normalised data for chart
    var seriesData = normalisedData;
    
    // Get max values for each axis
    var minY1 = 0;
    var minY2 = 0;
    var maxY1 = 0;
    var maxY2 = 0;
    for(var i = 0; i < seriesData.length; i++) {
        var _axis = seriesData[i].yAxis;
        var _values = seriesData[i].values;
        
        // Walk values and set largest to variables
        for(var j = 0; j < _values.length; j++) {
            // For maxY1
            if(_axis == 1) {
                if(_values[j].y > maxY1) {
                    maxY1 = _values[j].y;
                }
            }
            // For maxY2
            if(_axis == 2) {
                if(_values[j].y > maxY2) {
                    maxY2 = _values[j].y;
                }
            }
        }
    }
    
    // Set min, max values of axis
    chart.yDomain1([minY1, maxY1]);
    chart.yDomain2([minY2, maxY2]);
    
    // Set chart
    d3.select(svg)
        .datum(seriesData)
        .call(chart)
    ;

    // Auto resize chart on window resize
    nv.utils.windowResize(chart.update);
   ...