Meeting reporters in his new role on Thursday morning, Nolin said there's nothing the Senate can do about rules that require pension contributions to continue to be made for suspended senators Patrick Brazeau, Mike Duffy and Pamela Wallin.
Senators' rights can't be changed retroactively, he said.
When asked if he was nervous about what an ongoing audit might reveal about senators' use of expense accounts, he said "the big stories are behind us."
He speculated that Auditor General Michael Ferguson may disagree on senators' definitions of what constitutes a parliamentary function. He also said the audit might find examples of improperly charged lunches or Christmas cards mailed to the U.S. at extra expense.
"I don't like that," he said, "but we'll take it," pointing out that a June 2012 report was "clean."
"What happened between 2012 and now?" he said.
Nolin said a lot of money is being spent by Ferguson in order to do a thorough review.
Harper 'white, pale' during Hill shooting
Nolin, who was in the Conservative caucus room on the day of the shooting on Parliament Hill, also described his experience for reporters.
"I was glad that those doors were quite thick," he said.
"I saw my prime minister becoming white, pale," he said.
"We are not trained for that. I’ve seen military training in the past, but when you go through it, you live through it, it’s not pleasant."
Nolin said the shooting was "a learning event for everybody" and said both the Senate and the House of Commons are modifying security to better protect everyone who works on Parliament Hill.