I am also a Canadian nurse trying to work in the US. After I applied to the Washington state BON for licensure, I had to have my credentials evaluated by CGFNS (which took 6 months) before I could apply to write the NCLEX. Once I wrote the NCLEX, I did get my license in the mail within 2 weeks (maybe Washington is faster than other states?). As for applying for a green card, you can't do this on a TN visa, as it implies intent to stay permanently (which goes against the 'temporary' aspect of the TN). However, if you can get your employer to sponsor you for a H1B visa after you get a TN, then you can start the green card process (but it takes a long time, as they only give out a certain number of H1Bs a year).