Well... since you would be the one hiring the nanny, you would be the one who determines if the nanny is being taken advantage of or not. You're required by law to pay minimum wage, and overtime for anything worked more than 8 hrs/day. You're also required to provide room and board (and can then deduct an amount which varies by province from their pay... it's only about $350/month). So, the nanny should be getting, after tax and food and accomodation, around $800-$1000/month. That seems like a fairly reasonable amount to live on, when your basic living expenses (food and housing) are already paid for.
As far as training goes, they are required to either complete a 6 month caregiver course, which includes on the job training, or are required to have at least one year's of paid experience working as a nanny or in some sort of childcare capacity. I'm not sure what the rules would be for asking them to take courses while they're working for you... in that case I would expect that you should pay the course fees and also pay them for their time while attending the course.
WHen I was growing up my parents went through many live-in nannies. Some were great, others not so great, and others were just plain terrible (one of them left my 2 year old brother sleeping in his crib while she walked the 10-15 minutes to my school and back to pick me up. my mom has many more horror stories). My parents found that a great nanny was wonderful, but daycare was preferable to an average or terrible nanny. It feels like you'd be taking a big risk, IMO to leave someone alone with your kids for so long every day. Now, if you could get a referral from a friend or relative or something, then it might be a great solution.