Nxivm co-founder Nancy Salzman is expected to plead guilty Wednesday in Brooklyn federal court, according to newly released court documents.

It was not immediately clear which charges Salzman, who is facing a racketeering conspiracy rap, is expected to cop to.

Salzman is the first of those charged under the indictment — including leader Keith Raniere, “Smallville” actress Allison Mack and Seagram beverage heiress Clare Bronfman — to plead guilty.

In September, prosecutor Moira Penza let slip that Salzman was “continuing to engage in plea negotiations” with the government.

And her defense attorney Robert Soloway didn’t deny then that Salzman, known inside the group as “Prefect,” was speaking with prosecutors, but said Tuesday she wouldn’t be cooperating against her co-defendants as part of her plea.

“There is not a cooperation agreement on the table,” he told The Post.

Soloway declined to comment further.

The 63-year-old registered nurse would be a powerful get for the government, given her longtime relationship with guru — and alleged sex trafficker — Raniere.

Opening statements are currently expected for April 29.

Mack is accused of overseeing a secret sex cult within Nxivm, called DOS, in which prosecutors say women were starved, branded and expected to have sex with Raniere.

The US Attorney’s Office declined to comment.