The nuclear charge of an atom is determined by the number of protons in its nucleus. Helium (He) has an atomic number of 2, which means it has two protons in its nucleus. On the other hand, nitrogen (N) has an atomic number of 7, indicating that it has seven protons in its nucleus.
Since the nuclear charge corresponds to the number of protons, helium (He) has a lower nuclear charge (2) compared to nitrogen (N), which has a higher nuclear charge (7).