Can my wife who is USA citizen cross the border using her Nexus card, then apply for PR inland and OWP?
Yes. Note that she requires a passport for PR.
Yes, she has a passport but will she not require proof of status in Canada?
"If you (the principal applicant) are living in Canada, provide proof of your status in Canada (e.g. copy of temporary resident visa, study permit or work permit, temporary resident permit, including out of status documentation). If you do not have status in Canada, please provide an explanation on a separate piece of paper, as well a copy of any paperwork you have that is relevant to your status.
If she gets a stamp, that's her proof. If no stamp, then an explanation letter and her entry date.
So she came to visit me last weekend 11/20 and asked for a stamp she has since returned home and is planning on driving with me in the first week of Jan so five weeks after stamp, I assume that the stamp is no longer the proof as she will now return on a different date.
Couldn't we just go into immigration and ask for a visitor record? I am thinking we will have all the documents ready to submit and can have a copy of them with us.