If you want a chihuahua that doesn't shed much, look for one with a sparse single coat. The CORRECT coat on a smooth is a thick, double coat. You will see fur around the neck, the back of the legs, and the tail will be especially full.
Example... this is the correct smooth double coat .... notice how full the tail is.
Brody is an example of an incorrect smooth coat. It is a single coat, with no undercoat, and very thin/short. More like a doberman. He does NOT shed. He can sit on my lap when I have on white sweatpants and I can pet him for hours and when I get up, there is no hair on my pants.
So if you really want a chi, get a longcoat that is sparsely coated or a smooth coat that has an incorrect single coat instead of a double coat. You will easily tell the difference when you see them in person.
Are you looking at rescues?