He def has a border terrier look. I have a border terrier cross too. I don't see chihuahua though. I see westie (west highland white) or poodle. but he def has border terrier. He has the classic face and long legs. My poor border terrier mix has short stubby legs :/ My vet thinks mine has dachsund in him.
Keep yourself clean and bright, for you are the window through which you must see the world.