They make Star Wars shirts with Chewbacca on them that say “Chuy” underneath. They also make one that has R2-D2 on it with “Arturito”. We have both.
As many other diminutives of first names in any language, they come from endearng “baby talk” spoken to little children. So, it’s a “natural” to from Jesus, in Spanish it sounds Hesús, Hesoos, morphs into Hechooz, Hechooy, and from this just -chooy, Chuy. Also Hechooz-Hechoochooz-Hechoochoh-Chuchoh, another common diminutive for Jesus (Hesoos) in Latin American Spanish).
The Spanish language has a plethora of semi-official nicknames for nearly every imaginable given name, often quite dissimilar to the original name:
http://en.wiktionary.org/wiki/Appendix:Spanish_diminutives_of_given_names
There is no reason to believe that any one of them has an origin any more remarkable than any of the others. Jesus is not considered to be a remarkable name any more so than Mary or Mohammed in other cultures.
Does the bible have anything about Jesus returning twice?
That explains “Nacho” as a nickname for Ignacio then. Always wondered how that one came about.
obligatory XKCD
Sweet Zombie Jesus!