..... Right ?
cat = gato/gata
cats = gatos/gatas
What is the difference between nosso and nossos?
Nosso is for singular masculine nouns, nossos is for plural masculine nouns.
The speaker's pronunciation makes it sound like "nossu gatu". Is that the correct way to pronounce it?
Yes. The letter "o" at the end of words sounds like /oo/ in English.