Using trademarked names as nicknames

Kids do it all the time and if it's a kid's book I wouldn't worry about it. But kids are pretty good at coming up with original nicknames. I can't see Joe90 being used as a nickname - the nickname would simply be J or J9. Nicknames usually have meaning to those who dream them up but they don't have to be immediately apparent to strangers.

Use commonsense and don't deliberately stick your head in a noose. For instance do you really think anybody has a sole global right to prohibit the use of the name Bugs as a nickname?

But really, if you're so worried you have to ask why not avoid the problem by creating nicknames that fit and are obviously nicknames chosen by the characters rather than deliberately copying existing names.

Writing is about being creative and original.

Many times nicknames are often a contradiction to what is expected, which is why they work.

For example, I know a man who is six feet four and hefty who has been nicknamed "Tiny" since we were kids.

What about someone called "Smiley" who never smiles?

Someone who is stout can be called String Bean.

I would say to create nicknames that will make your character memorable.

William Faulkner had two minor characters in his famous Snopes Trilogy named "Montgomery Ward Snopes" and "Watkins Products Snopes".

caw

I have no clue what Joe 90 is/was, so I would stick with something the majority of your readers would know or recognize. If you have to stop the story to explain why his name is Joe 90 or somebody has to look it up, that's not going to have the desired effect; people might remember your work for the wrong reasons ("Yeah, they named these characters after a bunch of products I'd never even heard of, so I had to quit reading about 25 pages in.")