Axis.TickLabelPosition (PowerPoint)

Describes the position of tick-mark labels on the specified axis.

Possible Values are xlTickLabelPositionHigh - The top or right side of the chart, xlTickLabelPositionLow - The bottom or left side of the chart, xlTickLabelPositionNextToAxis - Next to the axis (where the axis is not at either side of the chart), xlTickLabelPositionNone - No tick marks.
ActivePresentation.Slides(1).Shapes(1).Chart.Axes(1).TickLabelPosition = xlTickLabelPositionHigh