The GAZ History Museum is the place to understand Nizhny Novgorod as an industrial city, not just a river-port and merchant centre. It covers the Gorky Automobile Plant from the early Soviet period onward, with cars, trucks, technical material, photographs, and factory history. For anyone interested in Soviet design or heavy industry, it is more distinctive than another general local-history museum.
The museum is south of the historic centre, near the plant district, so plan transport rather than assuming it fits into a Kremlin walk. The vehicle collection is the main draw, but the worker and wartime material gives useful context for how deeply the factory shaped the city.