In case anyone is curious about Aussie nicknames we have some very solid rules around them
1) if you name has a shorter version/nickname you use that. It's pretty uncommon to hear someone go by their full name (this is also a class thing. Upper class will be more likely to use their real name, lower class/country will get real creative with names)
2) if your name starts with a consonant then an -a your name can be shortened to that +az or that +azza (I.e Jeremy becomes Jazza, Barry becomes Baz, Sharon becomes Shazza)
3) if the -azza rules doesn't work you can shorten it and put an o on the end (Damien becomes Damo, Simpson becomes Simo)
4) or use a last name and apply the rules to that. Knew a lot of guys in high school that went by their last name in some form to a point I almost forgot their real name.
5) less common now but we used to do opposite or descriptor names (if you had red hair you were called bluey, if you were from France you were called frenchie)