Final answer:
The central text of Nichiren, a form of Mahayana Buddhism, is the Lotus Sutra. This sutra is regarded as the ultimate truth in Buddhism and is foundational to Nichiren Buddhist practice and belief.
Step-by-step explanation:
The central text of Nichiren Buddhism, a form of Mahayana Buddhism, is the Lotus Sutra. Nichiren Buddhism stresses that this sutra contains the ultimate truth of Buddhism and insists on the Lotus Sutra's capacity to lead all beings to enlightenment. Nichiren Buddhists believe in chanting the phrase 'Nam-myoho-renge-kyo' which is derived from the title of the Lotus Sutra, as a practice for attaining enlightenment. The Lotus Sutra is esteemed as the most important and comprehensive of all Mahayana Buddhist scriptures and serves as the foundation of Nichiren Buddhist teaching.