Question: How is Buddha-nature linked to Bodhicitta?
Answer: Buddha-nature is the universal potential in all sentient beings to become Buddhas (fully awakened in perfect compassion and wisdom). Since it is the only truly enduring (and pure) aspect of our being, we say it is our true nature. This is while our other aspects, as based on the three (impure) poisons of attachment, aversion and delusion do not truly endure, and are thus not of our true nature. Bodhicitta is the aspiration to actualise our Buddha-nature, while helping others to do the same, so as to guide one and all to become Buddhas.