Here are some possibilities :
1. He gave it to Taiji for manaoing her to unlock the phone.🤔
2. He gave it to studiowale bhaiya.😕
3. He decided to preserve it for Naina, for next meeting.😲
4. After seeing the historical photo of Naina he became Gajni for some time and forgot about the chocolates.( After seeing the old couples he came back to senses)
5. He is planning to send it forumwasis as IF dwellers has lots of "fikar" for him.
6. How do I know, Samir's chocolate Samir jane.😔
But, if he take those chocolates back at Somani house, then Dadi will positively steal those chocolates. Dadi toh hain hi imported cheson ki diwani.