Where does “Nestor” come from?

Nestor (French) comes from Ancient Greek Νέστωρ, from Ancient Greek -τωρ, from Proto-Hellenic *-tōr.

Ancestry of “Nestor”, step by step

Step	Language	Word	Meaning
1	Ancient Greek	Νέστωρ	Nestor
2	Ancient Greek	-τωρ	Used to form agent nouns
3	Proto-Hellenic	*-tōr	—