fyi old saturn = not gm
They were GM, and the 3.0L with a timing belt was used in more than just that car, but also the Saturn Vue, Cadillac Catera/Opel Omega (and a lot of other Euro-market GM vehicles), Cadillac CTS as a bored 3.2L variety for the first model year, etc.
Otherwise, all North American GM engines use a lifetime (essentially...I've known people to go hundreds of thousands of miles and never touch it) timing chain except for the--again, Euro sourced and unique--Saturn/Opel Astra with a timing belt 1.8L 4-cyl.
The timing chain is always something that often mystifies Honda, Toyota, Nissan, etc., etc. past owners who are used to their timing belt/water pump change at a certain mileage interval. A timing chain breaking, especially on a GM vehicle engine, is so far out of the ordinary, that it's rarely even thought of. It can happen, yes, but if anything and only after many, many, many miles would the chain even start to wear at all.