@Banksy maybe it would be best to explain what it is you want to do exactly and provide an example. What does it mean to ‘copy’ the chart. Do you want to refer to a different set of data and use the same chart? Do you want to do dynamic things?
What you can do is use OpenPyxl to place graphics on a sheet that you have created with Python.
I think what is possible is to provide an Excel file with a data sheet and a chart. Then you copy this file with KNIME to a new location and then fill the data sheet with new data.