Private Sub Worksheet_Calculate()
    Dim Nope As Integer
    ActiveSheet.ChartObjects("Chart 3").Activate
    ActiveChart.FullSeriesCollection(1).ChartType = xlColumnStacked
    ActiveChart.FullSeriesCollection("Limit").ChartType = xlLine
    ActiveChart.Deselect
End Sub

Private Sub Worksheet_Calculate()
    ActiveSheet.ChartObjects("Chart 3").Activate
    ActiveChart.FullSeriesCollection(1).ChartType = xlColumnStacked

    If ActiveChart.FullSeriesCollection("Limit") Is Nothing Then "do nothing here"
    Else ActiveChart.FullSeriesCollection("Limit").ChartType = xlLine
    End If

    ActiveChart.Deselect
End Sub