Which McDonald's product name became a major brand extension after its introduction in 1983?

Chicken McNuggets became a major McDonald's brand extension after their nationwide introduction in 1983.

McNuggets were developed as bite-sized pieces of formed chicken coated in batter and fried. McDonald's introduced them nationally in the United States in 1983, adding a chicken product with a distinctive name, shape, packaging, and dipping-sauce association to its core menu.

The product strengthened McDonald's branding because “McNuggets” followed the company's recognizable Mc-naming pattern while creating a separate product identity. Advertising and packaging made the nuggets familiar to families and helped broaden the menu beyond hamburgers.

The 1983 date refers to the national U.S. introduction, not the earliest development or every international launch. McDonald's had already introduced other major products, including the Filet-O-Fish in 1963 and the Big Mac in 1967. McNuggets became one of the chain's defining later products.