Final answer:
McDonald's first introduced the Chicken McNugget in 1983, which quickly became a popular menu item across the chain's restaurants nationwide.
Step-by-step explanation:
McDonald's first introduced the McNugget in the year 1983. The McNugget became a popular menu item that expanded McDonald's offerings beyond burgers and fries. Initially, it was trailed in select locations in 1981, but it was not until 1983 that Chicken McNuggets were available in McDonald's restaurants nationwide, delighting fans of the fast-food chain with a new innovative product that has since become a staple in their menu.