You must likely cannot directly convert .odc charts to Excel spreadsheets (.xlsx). Nevertheless, it may be possible to import the chart as an object to one of the lists in the workbook. This seems possible using any spreadsheet editor based on OTF scheme (Calc), but you can probably also achieve it in Excel itself.
Convert OpenDocument chart to Microsoft Excel Open XML workbook and spreadsheet.
We have found 2 software records in our database eligible for .odc to .xlsx file format conversion.
Multiplatform software - convert odc to xlsx on any platform
Full-featured spreadsheet tool from LibreOffice suite
Convert from odc file format
The tables with software actions are a good pointer for what a certain program does with various file types and often may give users a good hint how to perform certain file conversion, for example the above-mentioned odc to xlsx. However, it is not perfect and sometimes can show results which are not really usable because of how certain programs work with files and the possible conversion is thus actually not possible at all.
Spreadsheet program from OpenOffice.org productivity suite