Organizational charts are not a required disclosure item in the US. That means that companies can choose whether or not to include them in public documents (company filings) and on their websites. They may consider this proprietary information.
If they choose to make this information public, the most likely source will be the company 10-K report (assuming it's a public company) or Proxy Statement. Search on the company's investors' webpages, EDGAR, or use a financial information provider. Be aware that you may have to construct a chart yourself, that the information may be there in narrative form only.
Sometimes this information finds its way into other types of company or investor documents. Try Google searches on your company's name with different keyword phrases and filetypes (PDF and PPT are the best bets).
For example:
Allow time for this! You will likely have to scroll through far more than one page of results, and need to skim through the actual documents retrieved. Use your browser's Find In Page search ...