Hi Debster25,
We need to export this chart, modify XML file and import it.
The key XML strings we need to use is: <order alias="..." descending="true" />
The following is the step process:
1. As shown, this is a bar chart. The horizontal axis is the name of the Owner, and the vertical axis is the number of Account.

Click on "···" in the top right corner and then click on the Export Chart button.

2. Open the download XML file, then find this part: <entity name="...">...</entity>. In my XML file, it is this:
......
<fetch aggregate="true" mapping="logical">
<entity name="opportunity">
<attribute name="ownerid" alias="_CRMAutoGen_groupby_column_Num_0" groupby="true" />
<attribute name="parentaccountid" aggregate="count" alias="_CRMAutoGen_aggregate_column_Num_0" />
</entity>
</fetch>
......
Then we want to have this chart sorted by the vertical axis. We need to add a line of XML strings above </entity>.
It is <order alias="_CRMAutoGen_aggregate_column_Num_0" descending="true" />
In the double quotes is the alias of the vertical axis. Fill in the alias according to your chart.
Therefore, the downloaded XML file should be modified to:
......
<fetch aggregate="true" mapping="logical">
<entity name="opportunity">
<attribute name="ownerid" alias="_CRMAutoGen_groupby_column_Num_0" groupby="true" />
<attribute name="parentaccountid" aggregate="count" alias="_CRMAutoGen_aggregate_column_Num_0" />
<order alias="_CRMAutoGen_aggregate_column_Num_0" descending="true" />
</entity>
</fetch>
......
3. Import the modified XML file into D365. It is sorted by the vertical axis.

Please refer to this article for importing and exporting charts:
[View:https://crmbook.powerobjects.com/basics/analytics/charts-4/:320:50]
If my answer is helpful, please mark it as verified. This will help other users with the same theme.
Hope this helps.
Best Regards,
Lu Hao