Contracts have not been signed, but both fighters have verbally agreed to the matchup and date according to Campbell. UFC 279 will take place at T-Mobile Arena in Las Vegas.
Zach Rosenfield, Diaz's representative, confirmed the date and opponent of Diaz's next fight.
"This is a fight Nate has been asking for since the middle of April," Rosenfield told ESPN on Tuesday.
Diaz (20-13) has been vocal in 2022 about wishing to fight out his current UFC contract, which has one fight remaining. According to sources, Diaz's camp and the UFC were involved in discussions around a new contract, however the 37-year-old recently made it very clear he wished to fight out the deal.
One of the most popular fighters on the roster, Diaz hasn't fought since a decision loss to current UFC welterweight title challenger Leon Edwards in June 2021.
Chimaev (11-0) is coming off a decision victory over Gilbert Burns at UFC 273 in April. It was the most competitive fight of Chiamev's professional career, but it also came against a former UFC title challenger. Chimaev, who was born in Chechnya and now fights out of Stockholm, is one of the fastest-rising title contenders in UFC history. He is 5-0 since signing with the promotion in 2020.
"I am going to handle Nate Diaz's funeral with the UFC," said Chimaev, in a statement he provided in Swedish to his representatives.