The S-platform (more commonly referred to as the S-Chassis) was Nissan's rear-wheel-drive sport compact platform, produced from 1976 to 2002. It was sold in every major market where Nissan cars were available. It was usually equipped with an inline four cylinder engine, and had four seats in a two-plus-two configuration.
In Japan, they were mostly sold under the Silvia or Gazelle model name (with the only major exception being the S13 180SX) while export models were badged with names like Datsun Sakura, Nissan/Datsun 200SX (not to be confused with the North American Nissan 200SX, which was actually a Nissan Lucino, a completely unrelated FWD model), and Nissan 180ZX.
Hot Wheels' Datsun 200SX represents the North American version of the 1979-1983 third generation model, the S110 Silvia. This car was sold as Nissan Silvia and Nissan Gazelle in Japan, as Datsun Sakura in Mexico, and in various other markets as Datsun 180SX.
Hot Wheels' '96 Nissan 180SX Type X represents the top-trim Japanese market version of the 1989-1998 fifth generation platform, S13 180SX. The 180SX was unique in that it was sold in Japan alongside both its S13 Silvia twin and the S14 Silvia that replaced the S13 Silvia in 1994. The 180SX was sold in North America as the Nissan 240SX hatchback (the S13 240SX notchback was actually a Silvia with a 180SX front end on it) and in most other markets as Nissan 200SX. The export versions of the 180SX were discontinued with the S13 Silvia, leaving only the S14 Silvia available after 1994. The North American 240SX should not be confused with the similarly named but unrelated Datsun 240Z.
Hot Wheels' Nissan Silvia S15 represents the Japanese market version of the seventh (and final) generation of the model, the S15 Silvia. It was never sold in North America or most other markets, though that hasn't stopped some enthusiasts from finding the loopholes necessary to import one on the grey market. It was badged in Australia and New Zealand as Nissan 200SX.