Trumps a business first and foremost, he will always strike bargains and make appropriate deals with Russia and China.
Even when the trade war was at its worst between US and China, Trump knew when to back down and strike a bargain. I don't think he will use nukes tbh, i was more fearful of putin using nukes out of desperation than trump.
Plus Trump has a few other cards to play first before that option enters the mind. Such as a limited ground invasion utilising kurds-US forces to occupy iranian kurdistan or even bombing Irans oil facilities and de salination plants.