Assuming your requests are in this order in your collection 1 > 2 > 3 and you want to run your requests in the below order using postman.setNextRequest()
1 > 3 > 2?
postman.setNextRequest() is working as expecting in your example.
If you want to call request 2, then you’d need to use postman.setNextRequest("name-of-request-2") in request 3, so after request 3 has been completed it’ll run request 2.
Bear in mind, that after request 2 it’ll naturally go to the next request in your collection which would be 3.
So you’d want to use the below in request 2 to end the test run:
postman.setNextRequest(null);
Hopefully that made sense?
Also, if you want to run your test collection in the order 1 > 3 > 2, why not just move the 3rd request so it’s the 2nd request in the collection so it’ll naturally run in the order you want without using postman.setNextRequest();