Ronaldo, 37, would earn an annual salary of $119 million (£100m) during the 3.5-year duration of the contract.
Al-Nassr is also willing to compensate the five-time Ballon d'Or winner for the estimated $19 million (£16 million) he was set to receive during the final six months of his contract with Manchester United, which was terminated last week.
Ronaldo will reportedly make a decision after Portugal's run in the ongoing 2022 FIFA World Cup concludes, sources with knowledge of the negotiations told ESPN.
Saudi Arabia is reportedly hopeful that signing Ronaldo, one of the sport's most biggest stars, would help its efforts toward a bid to host the 2030 World Cup with the legendary forward acting as an ambassador for the country, according to ESPN.
Manchester United announced it reached a "mutual agreement" with Ronaldo to leave the club effective immediately on November 22.
"Cristiano Ronaldo is to leave Manchester United by mutual agreement, with immediate effect. The club thanks him for his immense contribution across two spells at Old Trafford," the club tweeted.
The statement came after speculation of the five-time Ballon d'Or winner's departure after Ronaldo criticized United and manager Erik ten Hag during a recent interview with Piers Morgan.
Ronaldo rejoined Manchester United last year after a 12-year absence, having agreed to a two-year contract with the club in August 2021.
The Portuguese native spent seven years with United (2003-09) before joining Real Madrid in 2009 and Juventus in 2018.
Ronaldo scored 145 goals in 346 appearances for United, which includes 19 goals in 40 appearances since rejoining the club in 2021.
"The club thanks him for his immense contribution across two spells at Old Trafford, scoring 145 goals in 346 appearances, and wishes him and his family well for the future," United said in a statement obtained by ESPN. "Everyone at Manchester United remains focused on continuing the team's progress under Erik ten Hag and working together to deliver success on the pitch."