If you are onboarding existing NSH Script JOB which is already created, then Portal doesn't allow any target modification to existing BSA JOB (Which will be shared by other users) at this point(BLP Version 1.2).(Which might impact other user, who might be owner of that job.) Customer can just say execute or execute against using Home page -> Operations and proceed.
This functionality is not enabled so as to protect current BSA JOB getting modified. Please, feel free to contact BMC Support on when this feature will be available/enabled.
Current Functionality provided is to have BSA JOB without/with any targets and then from Portal Home page, use execute or execute against.
is this issue exists for Portal 2.1 version also?