You can trick labview into putting a cursor on a chart, but it's buggy. When I do this, the cursor is there but it goes invisible when I'm not using it.
1. Make a graph. If you already have a chart, you can right click on the chart and Replace->Waveform Graph.
2. Add a cursor to the graph. (Right click on graph->Visible Items-> Cursor Legend; Right click on Cursor Legend -> Create Cursor -> Free)
3. Right click on the graph -> Replace -> Waveform Chart.
I replaced it from graph to chart but How could I get cursors position now?