Most of the things we know about Nalanda University are from Tibetan traditions and preachings. There are many accounts about Nalanda by Hiuen Tsang and Yijing who preached Buddhism in China by adapting many texts from Nalanda University.
Apparently, there are four doxographies on Buddhist philosophies taught at Nalanda which are as follows.
Along with these, for major preachings, Nalanda also focused on Vedic learning which revolved around Vedic texts, rituals, Samkhya, and the Vedangas. Medicine, law, astronomy, city planning, linguistics, and reasoning were also part of their curriculum.