"Fantasy" chips is a general categorization of chips made to look like casino-issued gaming chips, whether the casino named is/was real or not.
Also, if you revisit the Tangiers entry on ChipGuide, you will see 2 sets of chips identified. The 3, plastic movie prop chips from the movie Casino.
And the "poker" set, which I believe were created in the thousands as home poker sets, or perhaps as souvenirs from a chip show, are best described as fantasy chips.
Since the Tangiers is/was not a real casino, both of these chip sets are fantasy chips, but the smaller group better fit the definition of movie prop chips.
I hope this explains.