Nick flew out last week and spent America's Thanksgiving holiday with the "Baywatch" star and her family, and now brother Joe is in town.
The siblings and their fiancees were part of a group shot featuring friends and family, which was posted online on Monday, November 26.
"Mumbai nights," groom-to-be Nick captioned the picture.
His big brother also took to Instagram Story to share a photo of himself toasting Nick with a cocktail.
Nick and Priyanka have already obtained a wedding license in the U.S. to make sure their upcoming ceremony is recognised in both their native countries.
There's no specific date or details about the nuptials, but reports suggest the singer will make the actress his wife at the beginning of next month, with some expecting a weekend wedding before the start of next week.
The couple became engaged in July and Jonas and his fiancee, who at 36 is 10 years older than the singer, have been inseparable ever since. He has joined her in India for family events and she has been spotted at his concerts.
They first hooked up at the Met Gala in New York last year (2017), when Jonas' publicist suggested the dateless singer arrive with another one of his clients. Both the singer and Priyanka shot down dating rumours at the time.