They mean basically the same thing, "to correct." You can interchange them without affecting the meaning, but there are subtle nuance differences. Of the four, 纠正is the most direct (with the harshest meaning), and it calls to mind a military officer correcting a cadet because of the word "纠". (Or a teacher correcting a pupil). 修正 is the most "gentle" way to say to correct, because it means to "edit and correct." 更正is the most formal, and you'll find that word used in the sense of "erratum" in a newspaper article. Finally, 改正 is a pretty neutral term.