Correction. This event doesn't only support the Nemesis hypothesis.
More precisely it is evidence that something caused excess asteroid activity 65 million years ago. And therefore is supporting evidence for any theory which could explain that. Nemesis is the best known possibility, but is far from the only candidate.
The supposed impact is merely a data point that could be used to interpret Earth impact periodicity. It can only contribute to our to our current collection of data. Defining it as evidence in support or against periodicity is premature.
I was saying that it is evidence that the dinosaur asteriod was not just a random asteroid. Some external force disturbed potential asteroids and shoved multiple ones into the inner solar system. That fits with Nemesis. But would fit with other theories as well.
More precisely it is evidence that something caused excess asteroid activity 65 million years ago. And therefore is supporting evidence for any theory which could explain that. Nemesis is the best known possibility, but is far from the only candidate.