While the term “buddha-nature” does not appear anywhere in the Lotus Sutra, the teaching of what would later be called buddha-nature runs through it like a cord, defining one of its central affirmations. It is a clear aim throughout the sutra to persuade the reader that every living being, including and most importantly the reader, has within a potential to become enlightened, to become a buddha.

One’s buddha-nature is developed by following the Buddha-way, doing what buddhas have always done, bodhisattva practice. Central to the Lotus Sutra is the idea that Śākyamuni Buddha himself is, first of all, a bodhisattva. He has been doing bodhisattva practice, helping and leading others, for innumerable kalpas, and will continue to do so into the boundless future.

Because all the living have various natures, various desires, various activities, various ideas and ways of making distinctions, and because I wanted to lead them to put down roots of goodness, I have used a variety of explanations, parables, and words and preach various teachings. Thus I have never for a moment neglected the Buddha’s work.

Thus it is, since I became Buddha a very long time has passed, a lifetime of unquantifiable asamkhyeya kalpas, of forever existing and never entering extinction. Good children, the lifetime which I have acquired pursuing the bodhisattva-way is not even finished yet, but will be twice the number of kalpas already passed.

While it is very important that the Buddha and the śrāvakas are also in some sense bodhisattvas, it is even more important that you and I are bodhisattvas — called to grow in bodhisattvahood by leading others to realize that potential in themselves. To develop one’s buddha-nature is to do bodhisattva practice, to follow the role model of the bodhisattvas.
A Buddhist Kaleidoscope; Gene Reeves, The Lotus Sutra as Radically World-affirming, Page 193