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

Yes.

The word "nossas" is identical in meaning, spelling, and grammatical function in both Brazilian and Continental Portuguese. The only difference is pronunciation. In Brazil, vowels tend to be more open and the rhythm of speech is more syllable-timed. In Portugal, unstressed vowels are often "reduced" (pronounced much more softly or almost swallowed) and the rhythm is more stress-timed.

Brazilian Portuguese

1. As nossas meninas adoram o parque. (Our girls love the park.)
2. As nossas chaves sumiram. (Our keys disappeared.)
3. As nossas fotos no celular estão ótimas. (Our photos on the cell phone are great.)
4. As nossas bolsas estão no ônibus. (Our bags are on the bus.)
5. As nossas ideias para o café da manhã são simples. (Our ideas for breakfast are simple.)

Continental Portuguese

1. As nossas raparigas adoram o parque. (Our girls love the park.)
2. As nossas chaves perderam-se. (Our keys were lost.)
3. As nossas fotos no telemóvel estão ótimas. (Our photos on the cell phone are great.)
4. As nossas malas estão no autocarro. (Our bags are on the bus.)
5. As nossas ideias para o pequeno-almoço são simples. (Our ideas for breakfast are simple.)