We exploded several atomic bombs in LEO- Argus and Starfish Prime were two. They obviously had a very energetic yield but left no crater and no sign except for glows in the sky and fallout.
Tunguska was (maybe) a comet fragment that exploded fairly close to Earth and flattened trees, but no crater.
Meteor Crater in Az, now, IS a meteor crater.
There have been several big atmospheric ice explosions, many detected by our nuclear bomb watch devices. They happen.
If a chunk of ice or rock detonates in the atmosphere the energy of that blast can be compared to the energy release of a nuke. It explodes, but it's not a nuclear explosion, more like a huge blast of steam.
I've seen the aerial shots of Meteor Crater. Man, that thing hit pretty close to that road. It's a good thing no one was hurt.