The Nehvait photo game was planned to end the Mallika-Advait relationship, and through that, Naaz expected to end Nehmat's relationship with the Randhava siblings.
Initially, Naaz wanted to separate Nehmat and Ekam because she was jealous of their relationship (Naaz had this thought from the beginning). But after Nikhil came into Naaz's life, she wasn't really interested in Nehkam. Then Mallika and Naaz fought, and Mallika slapped Naaz. Thereafter, Naaz wanted revenge. That is why Naaz published the article. So Naaz isn't trying to separate Nehkam because of Nehmat's challenge. She wants to separate them because she is angry and doesn't want Nehmat to have any happiness.
No Naaz was always jealous of Nehkam's love bonding and their relationship since the very beginning, which could be clearly seen in the party she accompanied them, she was very well jealous in the party seeing Nehkam's trust on each other.
https://www.youtube.com/watch?v=gWP3tC1ORq4
https://www.youtube.com/watch?v=EHeilAztwRM
Furthermore, when Nehmat broke up with Ekam on Rupy's insistence, Naaz was really happy about their breakup even though it was only for a short period.
https://www.youtube.com/watch?v=HQd-cv3jO6o
So Nehkam's separation was always there in Naaz's subconcious mind because she had been always jealous about their love and trust on each other.
Which is why she had taken Nehvait's photos (Nehvait dancing together) and plotted against Nehkam even when she was in a relationship with Nikhil