Argentina:
Laws of Argentina are available in Spanish at http://www.diariojudicial.com/. You have to sign up but it's supposed to be free.

Canada:
Canadian laws are available in English at: http://laws.justice.gc.ca/eng/ and in French at http://laws.justice.gc.ca/fr/

Mexico
Some laws are available in Spanish from a government website (in Spanish) at http://www.ordenjuridico.gob.mx/
Some are avilable from the Mexican Congress website (in Spanish) at http://www.diputados.gob.mx/

Nicaragua
Laws are available in Spanish from the National Assembly website at http://www.asamblea.gob.ni/
The Supreme Court website (in Spanish) is at: http://www.csj.gob.ni/