There's a sample over here that will show how to set the first's chart title to the active cell:
function onOpen(){
SpreadsheetApp.getUi().createMenu('Charts').addItem('Update title of the first chart from active cell', 'myFunction').addToUi();
}
function myFunction() {
var sheet = SpreadsheetApp.getActiveSheet();
var chart = sheet.getCharts()[0];
chart = chart.modify()
.setOption('title', sheet.getActiveCell().getValue() || 'Empty')
.build();
sheet.updateChart(chart);
}
The script adds a menu and will update the first's chart title to the current active cell.
It would be interesting to do the contrary, for instance you may have multiple sheets and build charts from each sheet range. The script should allow to set the current selected chart's title to a give named cell.
Assuming the scenario above, and while a chart is selected, pseudocode:
Problems: