chance upon

blow one's chance

To ruin, or fail to capitalise on an opportunity.

Buckley's chance

A very small chance; no chance at all.

Chinaman's chance

No chance; zero possibility.

dog's chance

Little or no likelihood.

fat chance

Little or no chance, a low or nonexistent likelihood of occurrence or success; a faint chance.

fighting chance

A chance that is dependent on success in a struggle, with the implication that such success is not unattainable.

in with a chance

Having a chance.

jump at the chance

To immediately accept an offer; to seize an opportunity.