There's really nowhere our interests intersected -- Brasil was pretty far south, and we were never that involved in Africa (and Timor was tiny piddleshit territory). There's also the fact that Portugal was Anglo-aligned, which would have meant bigger problems.
As for a Black Legend, there wouldn't be one. The image of the evil Spanish was itself contingent on a) Spain having much flashier, much larger, much more brutal conquests and b) Spain's war against the Protestant Dutch and their role in the Lizzy-Mary fight. Thusly, the Black Legend was created around Spain's Catholicism and conquests. Portugal doesn't have the resume, and their Catholicism is less... severe than that of the Spanish, for whom it was basically an ideology on and off into the 1970s.