If you can't get rid of the smell by bathing, I would tend to think it might be coming from within. What kind of food are you feeding her?
Also, I don't know if it would work, but you could try the same recipe that you would use for dogs that have been sprayed by a skunk. NOT tomato juice! My friend is a groomer and she has some shampoo that really does a good job for skunk odor removal. Maybe your groomer will sell you some!
For home recipe use baking soda, peroxide, and Dawn. I'm not sure on the exact ratio, but I know that the Dawn is about one tablespoon, the peroxide is about one quart, and baking soda is maybe one-half cup. You can check it on line. I have had to use this quite a few times, unfortunately! So I always keep the ingredients on hand. HOWEVER - for a chi, I would just sponge the mixture on and work it in a little. I would do it like you would on a big dog. I use it liberally on my golden. But for a chi, I would be careful not to use too much. Then I would rinse well and dry her off! REMEMBER, the peroxide will lighten her color just a bit! But if it works, it might be worth it!