in this example, you can see how do you set label to show when the chart dont detected data, please remember use after section of chart:

 chartOptionsDonut:{
                                                            chart: {
                                                              type: 'donut',
                                                            },
                                                             noData: {
                                                                text: "No data text",
                                                                align: "center",
                                                                verticalAlign: "middle",
                                                              },