Complex sentence: During this time, she was also as a substitute anchor for "Today," and from May 2005 to 2011 also anchor of "Dateline NBC," and the primary substitute on "NBC Nightly News" from 2005 to 2011.
Split into simpler sentences: During this time, she also served as a substitute anchor for "Today". She was the primary substitute on "NBC Nightly News" from 2005 to 2011.