Plan around the state licence and the certification, which commonly take months. The immigration step is the last and by far the shortest part of the sequence.
Keep the Canadian job until the state licence issues
Start with the state board, because it is the slowest and least controllable element and because it depends on third parties sending verification directly. Apply for the health care worker certification in parallel, since it also relies on institutions responding. Only when both are progressing should the employer letter be finalised and a start date discussed, and only then does a border appointment or a petition matter.
Nurses in this position frequently reverse the order, resign a Canadian post on the strength of an offer, and then wait at home for a licence with no income on either side of the border. The safer sequence keeps the Canadian licence current and the Canadian job in place until the state credential issues, then moves quickly, because the immigration step itself is measured in a day.