That's actually a hell of a question.Hello Kitty isn't a chibi Hello Kitty. She's just Hello Kitty, as designed.
This is a genuine difference from calling something a waifu and claiming the character is 54 despite their youthful appearance without a separate baseline.
If Chibi just means "super deformed", what is the inverse of that for the Arby's waifu? How do you deform something that is undefined?