that Hispanic generally is used to refer to countries/people who speak Spanish or are from Spanish speaking countries originally. It's not really a racial thing. Lots of "White" people in Chili (Large German population) consider themselves Hispanic b/c they speak Spanish. Latino is the newer term and is generally prefered by the younger generations. I guess to distinguish themselves. And chicano as has been said before is Mexican America.
It's kind of the same thing with many Black people. some prefer Black, some pefer African-American, some really old people still say Negro. It kind of changes with each generation I think. My friend Sally hates to be called African American b/c she says she's not from Africa. She prefers Black. I guess it just depends on the individual
