Although the Theravadins/ Hinayanists have no the category of the "Buddha's Nature", all true Mahayanists (with exception of some Yogacarins) insists that all the sentient beings possess the Buddha-nature It is Tathagatagarbha, the Embryo of the Buddhahood in all beings.
Buddha exclaims in Avatamsaka-sutra:
The Tiantai-zong/T'iant'ai-tsung of the Chinese Buddhism teaches that even "non-continuums" (inanimate things) are also of the Buddha-nature.
How wonderful, how surprising! All the beings are already endowed with the wisdom of the Buddha! They have already all Buddha-qualities! How mysterious is it!
And the task of the bodhisattva who says: "My great vow is to save/liberate all the beings" (i.e. to assist them in awakening of this inner and hidden Buddha-nature which is the Clear Light) is just the same as the task of the Kabbalist in the raising up Holy Sparks.