Is the word chá the same in Brazilian and European Portuguese?

Yes

The word "chá" is identical in both Brazilian and Continental Portuguese in terms of spelling, grammar, and primary meaning (the infusion made by soaking leaves or herbs in hot water). There are no differences in how the word itself is defined or written. The only differences between the two varieties of Portuguese lie in the pronunciation (the accent and intonation of the speaker) and the surrounding vocabulary or sentence structure used when naturally expressing an idea.

Brazilian Portuguese Examples

1. Eu gosto de tomar chá de camomila antes de dormir. (I like to drink chamomile tea before sleeping.)
2. Você quer um chá gelado? (Do you want an iced tea?)
3. O chá de erva-doce é muito bom para a barriga. (Fennel tea is very good for the stomach/belly.)
4. Vamos fazer um chá da tarde? (Shall we have an afternoon tea?)
5. Eu preparei um chá de hortelã bem fresquinho. (I prepared a very fresh peppermint tea.)

Portuguese (Continental) Examples

1. Eu gosto de beber chá de camomila antes de dormir. (I like to drink chamomile tea before sleeping.)
2. Queres um chá gelado? (Do you want an iced tea?)
3. O chá de erva-doce é muito bom para o estômago. (Fennel tea is very good for the stomach.)
4. Vamos tomar um chá ao fim da tarde? (Shall we have a tea at the end of the afternoon?)
5. Preparei um chá de hortelã muito fresco. (I prepared a very fresh peppermint tea.)