Is it illegal to have for example: nike.ca domain registered if nike.ca was available? or any other extension of it .biz .info .mobi etc?
It's not illegal per se to register a domain name bearing a trademark unless any applicable law in your area says otherwise. What's illegal is using a domain with a trademark to make money off their trademark somehow. But then, some trademark holders are very aggressive in protecting their marks. Some even don't show mercy regardless of the costs. Be wary of who you're potentially dealing with.
Dave hit the nail on the head. Once you try to make money with a trademark domain it becomes illegal but a lot of trademark holders don't wait for you to cross that line. Some even have the sharks searching new domain registrations to pounce on any containing specific terms. Like Dave said - be wary.
No its not illegal. But if you misuse it such as use the domain to spread bad rumor then you can be prosecute in court