I've handled it by simply creating two charts, one with the logarithmic scale, and one with the linear scale. To switch between them, I use a cyclic group of fields "Logarithmic Scale" and "Linear Scale". These fields don't link to anything, have no data, and only exist to support the cyclic group. Then the logarithmic chart, for instance, would use a conditional show of getcurrentfield("Scale")='Logarithmic Scale'. Then you just need some way of displaying the cyclic group, such as with a list box (with nothing listed since there are no values).
You wouldn't need to use a cyclic group, of course. You could also just make a "Scale" field with values 'Logarithmic' and 'Linear' and set it to always have one and only one value selected. The main thing is just that I think it takes two charts being conditionally shown.
I suspect you could do it with a single chart and a macro, but I wouldn't due to the drawbacks of macros.
I highly doubt there's any way to do it with a single chart and an action, but I could be wrong.