Those who chant Nam-myoho-renge-kyo are themselves the treasure tower

In the Latter Day of the Law, no treasure tower exists other than the figures of the men and women who embrace the Lotus Sutra. It follows, therefore, that whether eminent or humble, high or low, those who chant Nam-myoho-renge-kyo are themselves the treasure tower, and, likewise, are themselves the Thus Come One Many Treasures. 22/4

The Writings of Nichiren Daishonin
On the Treasure Tower
Written to Abutsu-bo Nittoku on March 13, 1272