Since I will not be able to join as CTI since my wife is not a citizen, is it possible to joing as nuke and then cross over to cti after I my contract is up?
I know this is a bit early since I have not even went to boot and don't know if I would make it through A school for nuke but is there anyway in the future I would be able to?

I doubt that they'll let you cross rate if you go nuke. Nukes are one of the more difficult if not the most difficult rate to keep stocked with bodies. Plus it takes a lot of time to train a nuke. Maybe if you somehow could get it stipulated in your reenlistment contract that the only way you would reenlist would be if they let you crossrate to CTI. I wouldn't count on it though.