Assuming no agreement is reached between the parents, under the time line you describe, a motion requesting a modification would need to be filed in Nevada. There is the possibility that specific jurisdictional language exists in the prior order of custody that may impact this so I suggest you have an experienced custody attorney review all prior orders. A child of 13 may be viewed by some Judges as having something to say about where they want to live but the insights or preferences of the child are not the end of the analysis. Simply put, as a general rule, children do not get to decide where they want to live. The Family Court will examine the best interest of the child in determining the outcome of any modification request. The movant (in this case, Dad) would have the burden of evidence to show that the move is in the best interests of the child. Hope this helps.
More facts are needed. I assume you moved to Nevada with either dad's permission or an order from the Court. If there is an existing order in Ontario, that Order and jurisdiction controls. If your daughter is mature and can delineate valid reasons for wanting to go back to Ontario, you and your ex should attempt to mediate a resolution. It is possible that a Court will not listen to the input of a 13 year old. But only you know if she has valid reasons or if she just wants to be where she thinks she will have more freedom. In an ideal situation, you and your ex would get on the same page in your daughter's best interest, and present to her in an united front. As that doesn't happen often in family court, you will both expend much money litigating this issue.
My colleagues are correct. Your case will depend upon the language of the original custodial order (assuming you have one) and the nature of the reasons your daughter and ex want her to move back. (If no court order exists, then we have a different scenario.) And if Canada's custodial laws are similar to those here in Nevada, then yes, he can file a motion there. There may be some jurisdictional issues in Canada that would allow you to move jurisdiction here, so you should find an attorney in Ontario that can help. This is an international jurisdictional issue that will take someone of experience.
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