Currently there is no way to dynamically figure out approval chains. You can check out existing feature requests and up or down vote them.
There is an open enhancement request to have the system be able to pull the Manager field from AD/OpenLDAP (Ability to pull in Active Directory "Manager" field for use in Approval Process ) . However even if that was implemented is still requires that data to be correct.
Deepening on your use case you may also need to upvote this one for on demand approval processes (On-Demand Approval Process )