What does "no shot" mean?

No chance or possibility (expressing amazement and disbelief of an event).

No shot

phrase, slang

phrase, slang ·Uncommon ·College level

Phrase

1
No chance or possibility (expressing amazement and disbelief of an event). slang
"No shot!!! I just won the lottery!"
2
Used other than figuratively or idiomatically: see no, shot.
"While there is no shot specifically for monkeypox, data from trials with nonhuman primates suggested that vaccines against the closely related smallpox virus might also prevent transmission of this one."

"No shot!!! I just won the lottery!"

Possibly from shot (“an opportunity or attempt”) or as a euphemism of no shit.