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

No.

While the fundamental meaning of "chatas" (annoying, boring, or tiresome) is the same in both dialects, the typical usage differs. In Brazilian Portuguese, "chatas" is the most common and versatile word used to describe anything or anyone that is unpleasant, tedious, or boring. In Continental Portuguese, while "chatas" is understood and used, speakers much more frequently reach for synonyms like "maçadoras" (tiresome/boring) or "secantes" (dull/boring) to express the same idea.

Brazilian Portuguese Examples

1. Essas músicas são muito chatas. (These songs are very boring.)
2. As pessoas aqui são muito chatas. (The people here are very annoying.)
3. As aulas de história são chatas. (History classes are boring.)
4. As regras de etiqueta são chatas. (Etiquette rules are annoying.)
5. As novelas são chatas. (The soap operas are boring.)

European Portuguese Examples

1. Estas músicas são muito maçadoras. (These songs are very boring.)
2. As pessoas aqui são muito secantes. (The people here are very annoying.)
3. As aulas de história são maçadoras. (History classes are boring.)
4. As regras de etiqueta são secantes. (Etiquette rules are annoying.)
5. As novelas são maçadoras. (The soap operas are boring.)