Nintex Workflow and Access Control

Hello, can anybody help with getting owner permissions on Nintex workflows in Sharepoint 2010 with Powershell.

I also want to ask your opinion about Access control in Sharepoint 2010. Should all Access Control like AD, Sharepoint, Titus be in the hands of Administrator or some of it like Titus be in the hand of the Developers.

Best Regards Olafur_s

Icelandic DBA admin