This looks like another requirement for a text box instead of the chart's Y-axis label. You can add sub- and superscripts to text in text boxes. Apparently not in an axis label.
One other idea is to use special characters. In the Edit Menu, click on Special Characters. Look at Digits. One set of 0-9 is superscripts. But be careful, at least in one font they don't align on the same baseline. Click on the triangle next to "Font Variation" and pick a font where all 10 digits align. What you will do is click on the font variation (only required once to set it) then double click on 0-9, one at a time, and it will put those characters wherever the cursor is in your spreadsheet. If they are all aligned, use that font. Calibri seems to be a good font for them. You can change the font later using font settings in the toolbar. I guess you could find a good font that way too.
Message was edited by: Badunit
Message was edited by: Badunit