To delegate a principal (group or user) Full Control of an AD object from Powershell.
Assume the domain is test.local
Assume the name of the group to be delegated Full Control is Some Group
$ou="AD:\OU=Computers,DC=test,DC=local"
$group = Get-ADGroup "Some Group"
$sid = new-object system.security.principal.securityidentifier $group.sid
$acl= get-acl $ou
$ace= new-object system.directoryservices.activedirectoryaccessrule $sid,"GenericAll",Allow"
$acl.addaccessrule($ace)
set-acl -aclobject $acl $ou