Kardashian's Instagram account was deactivated on Wednesday after he posted the pictures, which he then shared to Twitter.
According to the California law, where Kardashian lives, it is illegal to intentionally distribute "the image of the intimate body part or parts of another identifiable person," commonly referred to as "revenge porn."
Kardashian also accused Chyna of infidelity and, according to the Associated Press, drug use, in his posts.
"We are considering all legal options and recourses at this time," Chyna's attorney, Walter Mosley, said.
People magazine reported this past February that Kardashian, 30, and Chyna, whose given name is Angela Renée White, 29, had broken up shortly after their one-year anniversary. In April, 2016, she announced on social media that Kardashian had proposed after a three-month courtship, and one month later, she revealed that they were expecting a baby.
Their daughter, Dream, was born last November.
A rep for Kardashian did not immediately respond when asked for comment.