How to receive job offer in Ontario?

Job offers come through the regional health authorities in virtually all provinces. Some health authorities have chosen to employ recruiters, but they are not the only way in the door. Ontario is a very large province with a huge population. You first need to choose a location in Ontario where you'd like to work, find out what health authority it is in and then check the careers section of their website to see what's available. You may apply for positions while working through the registration and immigration process. They may have a program that assists nurses with the registration and immigration requirements; they will have the most current information on how to navigate the system. Registration is handled by the College of Nurses of Ontario; they have absolutely nothing to do with obtaining employment and are purely regulatory in function. There are many complexities in the process of coming to Canada to work as a nurse; be prepared for a marathon.

You'll get a job offer from the hospital itself.

Employers always start the immigration process when it is work related, same thing in the US. You are unable to start it on your own.

There really isn't a difference. In BC, and most other provinces, the health authority is "the employer" and paycheques come from the region and not the specific hospital. The health authority acts as a central hub for human resurces and so all nursing positions available in the region will be posted by the authority and the immigration process started by the region, rather than the hospital. This model has some advantages. They say there is a reduced need for administration by reducing dupliocation of services (but I don't believe that is true, at least in Alberta...), better region-wide management of human resources, a single finance office, a single budget and so on. One big disadvantage is when it comes to floating. If you're "employed by the region", not the hospital or the unit, in theory you could be expected to work wherever they need a warm body. In practice that isn't what happens, but the threat is there.

Ontario also has health regions, but they have not moved to total centralization yet. So there the hospital is still the employer. You would apply to the hospital and they would then take over initiating the immigration processing for you. Does that make sense? (No, I know it doesn't really, but I don't know how else to explain it.)

To make it easier to understand, you are unable to start the process. It needs to be done by an employer, and it just comes down to who is the actual employer, the province or the hospital. But the same protocols are followed for hiring by both.

Hope that this helps.