My requirement is to send escalation mail at each level in organization chart.

how can one send mail to manager based on the organization chart

Could you please share more details about your scenario?

Do you want to send an email to the Manager within your Organization?

Further, could you please share more details about your organization chart?

I agree with @ScottShearer's thought almost. You could add the "Get manager (V2)" action of Office 365 Users connector within your flow to get the manager profile of a specific user, then send an email to the Manager based on the Mail dynamic content of the "Get manager (V2)" action.

I have made a test on my side and please take a try with the following workaround:

Add a proper trigger, here I use Flow Button trigger.
Add a Variables-> "Initialize variable" action, Name set to InitialUser, Type set to String and Value set to Test3@xxxxxx.xxmicrosoft.com.

Note: I assume that the user Test3@xxxxxx.xxmicrosoft.com is the lowest level member within your Organization chart.

Add a Do Until action, within Condition box, click "Edit in advanced mode", type the following formula:

@empty(variables('InitialUser'))

Within "Do Until" action, add a "Get manager (V2)" action, the User (UPN) field set to InitialUser variable. Add a Parallel branch action, within left branch, add a "Send an email" action, To field set to Mail dynamic content of the "Get manager (V2)" action, then add a "Set variable" action, Name choose InitialUser, Value set to Mail dynamic content of the "Get manager (V2)" action.

Within right branch, add a "Set variable" action, Name choose InitialUser, Value set to null expression. Then click "Menu" button-> "Configure run after" option, within the "Set variable" should run after panel, select has failed option as below: