I'm not an expert on Canadian Healthcare and Immigration but I used to live in the SE part of Michigan which shares a border with the Canadian province of Ontario (actually, the only geographical area in North America where the Canadian border crossing is south of the US mainland). I had classmates in my NP program who were Canadian nationals. Some ended up going back to Canada to work as NP's and some ended up working in the US. What I was hearing is that NP positions in Canada are government funded and that majority of funding are given to Primary Care NP's (the equivalent of the US FNP). There is a bigger chance of getting equivalency of your US education in Canada if you have a US FNP is what I was told. There is an ACNP program (Master's level) in Toronto but it sounds like the demand is not as high as Primary Care. The Province of Ontario offers certification exams for Primary Care NP, ACNP (adult or peds), and Neonatal NP. I have no idea how the other provinces regulate the NP specialty.
The bigger issue, I think, is that I know these classmates of mine are Canadian citizens and had gone back to their native country. Their only hurdle was having their US education validated as equivalent to the Canadian programs. As a US citizen, not only would you need to have your US education validated, you would also have to pass requirements to work as a foreign national in Canada. I know there are Canadian nurses all over the US by virtue of NAFTA (they qualify via the TN1 Visa) but I'm not familiar with how this could work the other way around (meaning, a US National working in Canada). I'd be interested to hear from experts...
An American educated FNP must write and pass the RN(EC) (registered nurse in the extended class) exam in Canada in order to apply for registration as an NP in Canada. In order to apply to write the exam, you must have your education evaluated by the College of Nurses in the province in which you intend to write. For all intents and purposes, the US FNP education is identical to the NP-PHC (primary health care NP), with the exception that currently in Ontario, you do not need a Masters in Nursing to write the exam (this will soon change). You may have a certificate, which is equivalent to the sum total of the clinical portion of a US based NP Masters. In fact, before Canada developed their own national exam for NP-PHCs, they used the ANCC exam. To complete the Masters in Ontario, we need to complete three more classes (grad level stats, research and theory) as all the NP classes are offered at the Masters level.
Then, if you are successful writing the CNPE and successfully register as an RN(EC) NP, you still need to address the issue of working in Canada. To do this, you must either be a Canadian citizen, a permanent landed immigrant (permanent resident), or have a work Visa (not that easy to get, from what I hear). So while the US historically has helped Canadian nurses to get a US visa to work because of the greater unmet need (at least it was so in Detroit), Canada has far fewer positions available and does not need to recruit foreign nurses.