Excuse me if I am incorrect, but I do believe that what you’re speaking of would be patriotism. Nationalism is the ideological belief that your nation should be independent and united; it can mean different things, of course. For the Italians it meant removing foreigners from controlling their nation and uniting under one government. For Scottish National Party it means seceding from the United Kingdom.
It was often associated with secularism/deism in the 19th century, but this was not always the case. The ultimate goal of nationalists was to simply end petty wars that resulted from the arbitrary rule of monarchs and to unite as one people. Whether that also means disestablishing religion, like it did for Garibaldi, or for maintaining a conservative social order like for Bismarck, is a complicated issue.