Compatibility summary
You will need a travel adapter in Saint Kitts and Nevis; plug types used there differ from Brazil. Voltage differs by more than 20% — a voltage converter may be needed for some appliances.
Plug comparison
Brazil plug types: C N
Saint Kitts and Nevis plug types: A B G
There is no common plug type between Brazil (C N) and Saint Kitts and Nevis (A B G). You need a travel adapter.
Voltage comparison
Brazil: 127V, 60Hz
Saint Kitts and Nevis: 230V, 60Hz
Voltage converter recommended (Brazil 127V vs Saint Kitts and Nevis 230V).