Hi,

Code:
    Dim chtChart    As Chart
    
    Set chtChart = ActiveSheet.ChartObjects(1).Chart
    
    With chtChart
        If Not .Axes(1, 1).TickLabels.Font.Bold Then .Axes(1, 1).TickLabels.Font.Bold = 1
        If Not .Axes(2, 1).TickLabels.Font.Bold Then .Axes(2, 1).TickLabels.Font.Bold = 1
    End With