We cannot customise the outcome of Task Approval. Instead, use Assign Flexi Task where options are provided to customise the task outcome.
Below is Task Approval which does not provide an option to customise the task outcome:
Below is Assign Flexi Task which provides an option to customise the task outcome and same reflects in the approval Nintex form:
First response applies in the Assign Flexi Task vs. the same option in Request Approval are two different things. In Assign Flexi Task, it means that once something is Implemented/Not Implemented by the first approver, the second approver will recieve an email notification that their response is not required. With Request Approval, if it's Not Implemented for the first approver, you can do your rejection scenario, and if it's Implemented for the first approver, it goes to the second approver. See the difference?.. Is there a setting in the Assign Flexi Task to make sure that when something is approved by the first approver, it still goes to the second approver?