Sneaky Dee's is THE place to go for nachos in Toronto, hands down. It might not look appealing from the outside (to some) but you'll change your tune after the first bite.
I'm a vegetarian, and although I can't make friends with salad I certainly have picked up a few with the vegetarian Kings Crown.
Wednesday night is the Kings Crown + Pitcher special. If you're going to try their nachos, I highly recommend starting with Kings Crown (you'll never go back).
Don't worry vegans, they offer victimless nachos for you too :)
For all you beer lovers, there is a great selection to choose from (bottle and tap).
I *heart* Sneak's.