Why did the revolutions and nationalist movements of 1830 fail as compared to the success of 1848?

Well because the revolutions of 1848 were animated by nationalism and socialism.

Revolutions of 1848, series of republican revolts against European monarchies, beginning in Sicily, and spreading to France, Germany, Italy, and the Austrian Empire. They all ended in failure and repression, and were followed by widespread disillusionment among liberals.