Ms. Machado has firmly embraced President Trump’s military buildup and has publicly expressed her support for using force to oust the Venezuelan president, Nicolás Maduro.

She has also repeated debunked claims that Mr. Maduro manipulated U.S. elections, fueling accusations that she is amplifying misinformation to gain favor with the Trump administration.

“It will be a different kind of Nobel Prize ceremony,” said Benedicte Bull, a professor at the University of Oslo and a leading expert on Latin America in Norway. “Much more politicized than what we have seen before.”