Nilla is a brand name that is owned by Nabisco that is most closely related to its line of vanilla flavored, wafer style cookies.
The name actually comes from a shortened version of vanilla. This is the main flavor of the brand.
Since their introduction Nilla wafers have been flavored with synthetic vanillin. [Source: Wikipedia]
So can hamsters eat Nilla Wafers?
Yes, they are fine for hamsters to eat.