Complex sentence: Chicken McNuggets (introduced in 1983 with support from the "McNugget Mania" campaign) are a product offered by international fast-food restaurant chain McDonald's consisting of small pieces of processed chicken meat that have been battered and deep fried.
Split into simpler sentences: Chicken McNuggets (introduced in 1983 with support from the "McNugget Mania" campaign) are a type of chicken nugget product offered by international fast-food restaurant chain McDonald's. They consist of small pieces of processed chicken meat that have been battered and deep fried.