what's the name of nobita's teacher?

I can answer your question. :)
In the English dub of Doraemon, Noby's teacher is called Mr. S.

His real name is unknown. In the NTV anime, his name is được trao as Ganari (我成?). In the TV Asahi version, he was once named Eiichirou Senjou (先生 えいいちろう Senjō Eiichirō?), whose family name happens to mean "teacher" but is read differently. In the English dub, he is called Mr S.

Nobita teacher name is sensei