Upvote:4
Brazil does require visas for Indian citizens, and U.S. visas are not sufficient.
This is not a ridiculous question, however, as many countries allow foreign nationals entry with U.S. visas. Mexico allows entry with only a U.S. visa, though they also issue Mexican visas, and Turkey allows evisa entry to nationals of all Arab League countries who hold a U.S. visa.
While it might seem patently obvious that Brazil is a separate country, and would therefore have separate visas, not all countries have the infrastructure to issue visas worldwide. Accepting U.S. visas in lieu of or in addition to border-issued visas is one strategy, since the U.S. personally interviews and screens nearly all visa applicants.