Seyed Ali Shobayri, Seyed Ali Shobayri is of mixed Iranian and Scottish descent who found the path of the Ahlul Bayt (a) by his own research. He holds a BA in Islamic Studies from Middlesex University through the... Answered 4 months ago

Bismillah, 

Asalamu Alaykom, 

If you are 100% sure that the chocolate packet touched a part of the floor that definitely became najjs, and that the chocolate packet had moisture on it, then yes it would be najis. This would easy to purify as you could merely put the packet under a tap or just remove the chocolates. If however the floor was dry and so was the packet, then it isn't najis. 
 

May Allah grant you success