Diddy says NBC's crossed a very expensive line by putting out a documentary accusing him of murdering Kim Porter and having sex with 2 underaged women ... and now he wants at least $100 million from the network.

Diddy filed the lawsuit Wednesday morning in New York State, ripping NBCUniversal for "Diddy: The Making of a Bad Boy" ... a documentary streaming on Peacock. While the federally indicted mogul has seen and heard endless allegations against him -- from the feds and in a slew of lawsuits -- he says NBC "maliciously accuses" him of murdering "the love of his life and mother to his children."

In the docs, obtained by TMZ, Diddy blasts NBC for that particular claim because the L.A. County Coroner confirmed Kim's death was from natural causes and there's no evidence of foul play. He's also pissed the documentary amplifies YouTube conspiracy theories claiming it can't be a "coincidence" Kim and others in Diddy's world have died.

According to the suit ... the documentary leans into allegations Diddy had sex with minors, but he says that false claim is based on a civil lawsuit from someone claiming to have seen him with 2 girls. Diddy points out that the suit was already discredited by the 2 women in their 30s who've come forward and said they were adults at the time of that sexual encounter.

Diddy's suing NBCUniversal and Peacock TV for defamation, and he's seeking a minimum of $100 mil in damages.

Diddy's attorney Erica Wolff says, “In making and broadcasting these falsehoods, among others, Defendants seek only to capitalize on the public’s appetite for scandal without any regard for the truth and at the expense of Mr. Combs’s right to a fair trial. Mr. Combs brings this lawsuit to hold Defendants accountable for the extraordinary damage their reckless statements have caused.”

We've reached out to NBC for comment, but no word back yet.