Northanger Abbey is the first novel written by Jane Austen. Finished in 1803, it was not actually published until 1817, after her death. The heroine of the novel, Catherine Morland, is keen on Gothic fiction and begins to expect her life to work on the same lines as the novels she reads, especially on a visit to the old estate of her love interest, Henry Tilney. Austen skilfully parodies the Gothic novel, as well as satirising high society and its view of marriage.
The ‘tirade’ referred to here is uttered by Henry Tilney, Catherine’s eventual husband, in response to her describing Ann Radcliffe’s Gothic novel The Mysteries of Udolpho as ‘the nicest book in the world’:
‘"Very true," said Henry, "and this is a very nice day, and we are taking a very nice walk, and you are two very nice young ladies. Oh! It is a very nice word indeed! It does for everything. Originally perhaps it was applied only to express neatness, propriety, delicacy, or refinement—people were nice in their dress, in their sentiments, or their choice. But now every commendation on every subject is comprised in that one word."’
(Chapter 14). Find the full text of Northanger Abbey here.