If you are really stuck you may want to try PRIMO (our main "search [almost] everything") database or Academic Search Complete, for in 99% of cases you're going to want to stick with America: History and Life.
Provides full text coverage of the history and culture of the United States and Canada from prehistory to the present. Includes nearly 200 journals and 100 books, selective indexing for over 1,700 journals, and abstracts in English of foreign language articles.
Know Nothings (in particular, he is looking at the Bedini Riot in Cincinnati 1852, but if there were anything in Special Collections related to the Know Nothings, that would be great.)