A Swedish Chef is a cook from Sweden.
Also, it's a character from the MuppetShow?. He often tries to kill his meals right before cooking them, which fails in most cases (e.g. turtle soup, BigBird? at Christmas). He speaks something the makers of the Muppet Show must have confused with a Swedish accent. By watching the show, you may learn that Swedish people like to throw their kitchen tools around before they present recipes to a larger audience. This is, however, probably not the case.
Unreasonably, the Swedish chef is also quoted as one of TheBorg collective. It is pretty unlikely the Borg would assimilate someone like the Swedish chef, as his cooking techniques are far from technologically superior.