Use the cool grey 20 (E0E3E9) by default for the chip’s background, in order to make them stand out from the inputs’ background.
The embedded text or digital content will define the size of the container.
For readonly chips, you may use different backgrounds, considering our accessibility standards. Use an appropriate color that is connected to the description and context of the flag. The colors should be accessible : therefore, you can use white or black text.