Ok now where do you see that on the UI ?If you want to have a one button to launch all nukes, it already exists. It's called leave the game button. Let the cpu take over for you and it will launch all the nukes and u can come back after
If you hit the ESC key and bring up the menu ,there is a leave the game button but it just stops the game and brings you to the menu and then you will have to start the whole game all over again.