What Breed Is Our Dog?

We've recently gotten a puppy free from a person stating he was a Chihuahua. But let me first say that whatever he may be, we love him and we're glad we've been able to give him a happy home! We're just curious to see if anyone else sees what we see, that he may be a Chihuahua mix? I don't personally think he's a Chihuahua. Thank you!