A great deal. Nuclear weapons are not infinitely large or powerful. Here[1] is an account by Akiko Takakura. She was less than 300 meters from the hypocenter

A great deal. Nuclear weapons are not infinitely large or powerful. Here[1] is an account by Akiko Takakura. She was less than 300 meters from the hypocenter (the point on the ground directly below the nuclear blast) of the Hiroshima attack. She and others survived because they were inside a well built bank. She was 20 at the time and lived another 40 years. There are a number of things you can do to contribute to your survival and minimize long term consequences. First is distance; the further you are from a target the better. Assuming you have sufficient distance then you need shelter, anything you can put between you and the blast will help mitigate or entirely eliminate the impact; a hill can make an enormous difference. Should you have the good fortune to survive the blast then you need to deal with fire (nuclear blasts ignite many things simultaneously) and avoiding the bulk of the fallout until you're clear of the damage. If you manage all that you can indeed survive and live a long life. Much contempt is shown toward the old cold war era videos one can find of school children practicing nuclear attack drills by diving under desks and covering their heads. The fact is that these are entirely legitimate tactics that will mitigate the effect of the light flash, thermal pulse, flying glass and other debris. [1] https://www.inicom.com/hibakusha/akiko.html https://www.inicom.com/hibakusha/akiko.html