There is a thing called "recency bias." Nola pitched like a Cy Young candidate for four starts before the two duds. It's all normal ups and downs even given his history in September. And the team has plenty of data about his pitches (velocity, break, shape, execution) to assess whether it is fatigue (as well as more knowledge than us about whether it would help). In 2019 they tried giving him an extra day's rest between September starts and it didn't help at all, even though his career data says it does.
Plus - while I'm in the camp that says the season is already all but over, nothing to worry about - what are we going to do, give Walker or Tyler Phillips one of Nola's starts?