I don’t know about Brazil specifically but generally speaking there is no reason this should be a problem even if these things are rarely defined explicitly anywhere. In practice, if you are asked about other nationalities (which would be unusual except perhaps if the border guard notices that you are traveling from/to the US without a visa), lying sounds like a bad idea, just tell the truth and nothing much should happen.
Two exceptions come to mind:
If you travel from USA to Brazil, you will need both passports – the US one to leave the USA (source) and the Colombian one to enter Brazil.
Certainly you will have to show the airline your Colombian passport to proof that you’re allowed to enter Brazil.
The only thing you must keep in mind about dual citizenship is that, if you go to Brazil on your Colombian passport, in case of an emergency, the US Embassy may not give you diplomatic protection since you are a Colombian citizen in Brazil. From travel.state.gov :
In addition, their dual nationality may hamper efforts to provide
U.S. diplomatic and consular protection to them when they are abroad,
especially when they are in the country of their second nationality.
Credit:stackoverflow.com‘
4 Mar, 2024
5 Mar, 2024
4 Mar, 2024