The nerves and tension, at least, made this more believable. Remus would have been more worried had Nott seemed casual about meeting with him.
He picked up the glass of firewhiskey and noted the look Aberforth was giving him. He answered it with a meaningful look of his own, knowing that Aberforth would keep a watchful eye on whatever was happening here now, and then took his glass to a table near the center of the pub, where he sat, his back to the wall so that he was less open, and sat his glass down.