I heard that for NMIMS, Mumbai you have to take NMAT before 28 Nov 2021. Is this true?

No there's nothing as such. There are a total of 5 windows please go through the same on their website and book your date accordingly.

Hi
No This is not true , you can take NMAT in any of the windows and just only your first attempt will be taken into account for NMIMS Mumbai .

Thanks Shivam :)