Just adopted this little nugget yesterday - is he a Chihuahua?

They said he's a rat terrier mix but I'm thinking Chihuahua - he's 5lbs soaking wet and his entire body is about the size of my hand. Already he's shadowing me and attacking me with kisses if I leave the room for 5 minutes 😂 he's 2 years old they say, and came from a rural south Texas shelter.