https://imgur.com/a/BRi43tR

Neutral nucleophiles pretty much always gain a positive formal charge upon attacking something because they are attacking with a lone pair that formally belongs to them, and that lone pair forms a bond with an electrophile.

This results in a bond where the electrons that previously both belonged to the nucleophile now are shared between the two atoms.

This formal positive charge is often immediately dissipated by the deprotonation of the species.

A nucleophile is electron rich, which can mean it has a formal negative or an excess of electrons BEFORE attacking. After it has acted as a nucleophile, the product tends not to be considered a nucleophile anymore (at least without further deprotonation).

It has already "nuclophiled" and settled down.