Complex sentence: The interview on "Primer Impacto" was watched by 4.5 million viewers; it was the most-watched program that night according to the Nielsen ratings, and became one of the most-watched Spanish-language programs in American television history.
Split into simpler sentences: The interview on "Primer Impacto" was watched by 4.5 million viewers, the number one program that night according to the Nielsen ratings. It was among the most-watched Spanish-language programs in American television history.