The newly-married couple is in Delhi, India still celebrating their nuptials. The whole fam bam -- including his big bro, Joe Jonas, and his fiancee, Sophie Turner -- is at a reception ceremony that was also attended by the Indian Prime Minister Narendra Modi. Yes, Priyanka's a big deal in India.

As we reported ... Nick and Priyanka's multi-day party included a traditional Christian wedding ceremony as well as a Hindu wedding ceremony that included an intense dance-off and fireworks over the Jodhpur Palace.

The festivities started with a pre-wedding ritual called puja -- like a prayer service -- at Priyanka's parents' house. It was followed by a seemingly endless party all over the Indian country. Tons of guests too ... reportedly more than 200 guests got treated to the wedding of the year.