The nuclear charge of an atom is the measure of the effect of attraction between the protons in the nucleus and the outer electron
Shielding is the effect of the inner shells of electrons on weakening the attraction between the protons in the nucleus and the outer electron.
Nuclear charge is a measure of the effect of the number of protons in the nucleus and their ability to attract the negative electrons in orbits around the nucleus.
Shielding is the measure o the effect of inner sub shells of the S P D and F on their interference of the nuclear charge of the protons on the valence electron.