But he was quick to add, "Look, people are talking about it, so I think it's working for what she wants."
And Nick, who once dated Cyrus, noted, "She's smart. She's very smart. We've always known that about her. She'll always be successful."
As for the "Wrecking Ball" singer's unforgettable moment at the VMAs, Cyrus' ex admitted, "[The performance] was funny — I was laughing."
"Joe, you're the one who dumped Taylor Swift ," Rivers remarked.
"I think it's me and a few others, but yeah," replied the 24-year-old with a smile.
Meanwhile, the Jonas Brothers' new album, V, is reportedly due out sometime this fall.