Please refer to below link on building a sample organisational chart:
You can also acheive it with Sankey diagrams. Please refer below link which have very detailed explanation given by Olivier CATHERIN. It involves several calculations to get the flowchart as there is no direct option available for this in Tableau.
Hope this helps!!..
It is possible to build the flowchart in Tableau, kindly follow the below links:
These links will drive you to the desired result.