One popular Canadian slang term for "shut up" is "Nize it" or "nize that." This term is used to politely ask someone to stop talking or to calm down in a given situation. It can be used as a demand, request, or suggestion, depending on the context in which it is used. For example, if someone is talking too loudly or behaving aggressively, you might say, "Nize it" to indicate that they should quiet down or relax.

Another Canadian slang term for "shut up" is "Chew," which is used in a similar manner to "Nize it." This term is often used in a more casual or joking context, but it still carries the same message of asking someone to stop talking or be quiet. For example, if a friend is talking too much or saying something inappropriate, you might playfully say, "Chew, buddy," to indicate that they should stop talking.

When it comes to Canadian slang for "shut up," it's important to consider the context in which these terms are used. While "Nize it" and "Chew" are common expressions in Toronto and other parts of Canada, they may not be as widely understood in other regions or countries. 

In conclusion, Canadian slang for "shut up" includes terms like "Nize it" and "Chew," which are used to ask someone to be quiet or calm down in a given situation. Understanding these slang terms can help you connect with your Canadian audience and communicate more effectively in your writing. Next time you're in Toronto or chatting with Canadian friends, try using these expressions to see how they resonate in real-life conversations!