Contact the AKC breeder referral and get a list of reputable breeders in your area. Find one that will evaluate your dogs for you to see how they compare to the standard. If they are good candidates, ask if the breeder you've met will mentor you and let you learn from them about how to go about breeding dogs. Then and only then, after you've learned everything there is to know about doing the responsible thing, if your dogs are good representations of the breed then proceed. There's a world of potential heartache and dangers you could be facing in breeding chihuahuas so make sure your educated before doing so.