A child must live in California for 90 days before California can take jurisdiction. Since it appears your child has lived in California for an extended period of time then California has jurisdiction over all issues of custody. If you take the child to another state, you would have to check with that state's laws as to how long your child would have to reside there before you could bring an action in that state to establish your child custody rights in that state.
The problem you face is that if the father files in California to have you return the child to California before you have been in Nevada (or another state) for a long enough period of time the court might require you to return with the child to California. However, it doesn't appear that the father has been the primary custodian of the child and that is a good thing for you. IF you have further questions you should speak to a child custody lawyer in the town where your son resides who is familiar with these issues. Good luck
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