Hello & welcome. Can I suggest you search the term "teacup" on here, and other reputable sites.
Unfortunately, there is no such thing in ANY breed, and tiny supposed "teacup" pups are just that, very tiny (as in the tiniest/runt of the litter), born prematurely etc. Many breeders will actually even go to the extent of havimg caesarian operations done early just so they can sell them at 8 weeks when they're obviously so much tinier than a "normal" Chi and therefore they can perpetuate the lie of the "teacup".
We Chi people call them "tinies" - my last baby was a "tiny", more by accident than design (I bought him sight unseen and didn't care a hoot about his vital statistics, in fact, I didn't even ask) - I don't care if he ends up being twice the size & weight of a "normal" but I can only imagine how someone who got duped into paying a King's ransom for a "teacup" that ends up growing at a huge rate of knots & surpassing its peers must feel.