1801, "act of rendering national in character," from nationalize + -ation. Meaning "act of bringing (property) under control of the national government" is by 1864.
1794, "invest with a national character;" see national + -ize. Probably inspired by French nationaliser, noted by 1795 as one of the coinages of the Revolution. Meaning "bring under state control" is from 1869. Related: Nationalized; nationalizing.