If the child is born in Canada, then a court in that country will likely have jurisdiction pursuant to the rules and laws of Canada, its provinces, and localities. It is more than likely that you will be able to establish your paternity and establish custody orders, but you should seek the assistance of an attorney who is licensed to practice in that jurisdiction in order to enforce your rights as a father. You should look for attorneys that are based in the vicinity where your wife is staying and they will be better able to assist you with your case.
In addition to my colleagues valuable advice, you also need to speak with your immigration attorney or INS about the green card and your sponsorship. They need to know you have been abandoned and are withdrawing your sponsorship.
Responses are for general information purposes only, and are based on the extremely limited facts given. A consultation with an attorney experienced in the area of law(s) indicated in the question is highly recommended. Information and advice given here should not be relied upon for any final action or decision, as the information is limited by its nature to the question asked and the fact(s) presented in that question. THIS RESPONSE DOES NOT CREATE AN ATTORNEY/CLIENT RELATIONSHIP, particularly considering that the names of the parties are unknown.
As a side note to the answers given, Nevada has jurisdiction over the marriage for purposes of a divorce, and you can also request custody be addressed since the child was conceived here, but that issue is stayed until after birth. The likely outcome after much expense in attorney fees is unfortunately that Canada will assume jurisdiction of the child born there. So be prepared with a knowledgeable attorney there.
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