Its called Badge Engineering or Niche Marketing. The Chevy Optra is actually a Daewoo, rebadged by chevy.
The Khyber (known in PK) was sold as Holden Barina in Aussie. It was also sold as Geo Metro in USA.
Geo Tracker and Chevy Side Kick, actually Suzuki vitara, were also rebadged for Chevy.
Its not true that GM has stakes in Suzuki, Isuzu or Toyota, its just collaboration. For example, Toyota used to sell Chevy Cavalier as Toyota Cavalier in Japan and a redesigned Corolla as Geo Prizm in USA.
Even Isuzu used to sell its Storm sports car to Chevy as Geo Storm. Remember Honda used to rebadge Isuzu Frontera as Honda Passport and Vauxhall Frontera.
There are so many examples, I just gave a few hints.
A few pictures will follow....