According to Foreign Perfidy Policy, these are the twitterers that will best serve you for the region and form part of their new “top 100 twitter accounts” list:
Randy
Archibold (@rcarchiboldNYT) — New
York Times correspondent in Central America.
Mariano
Castillo (@marianoCNN)
— CNN’s Latin America news desk editor. A good all-purpose feed.
Damien
Cave
(@damiencave) — New York Times correspondent in Mexico.
Gabriel
Elizondo (@elizondogabriel)
— Brazil correspondent for Al Jazeera English, based in São Paulo.
Of those, your humble scribe fully recommends Gabriel Elizondo, who may be base din Brazil but has a great grasp of the whole region.