Meaning:
Lit. “nothing to pick up” is a bit toungue-in-cheek way to confirm that someone has been beaten comprehensively and beyond doubt. Also a way to brag about this if it’s you or your mates that done this. In a similar manner to pozamiatane.
The origin of the phrase is quite sad: if someone or something is destroyed beyond repair in an accident or a military attack, then this saying can be applied. And it sometimes is, for instance if a car is totalled or a motorbike collides with a car and the cyclist is thrown into the air to land far away. But obviously, you would not use it while talking to the casualty’s relatives.
You can also use it to admit a defeat on your behalf.
Examples:
No powiem wam, że jak HBO zrobi serial to nie ma co zbierać, niemal cały odcinek siedziałem jak na szpilkach
Raczej prosty siłowy tenis, mocny forhend, bardzo mocny serwis, jak trafi to nie ma co zbierać, bekhend słaby technicznie jednoręki.
A później przyszło uczucie totalne porażki. Przegrałem. Pozamiatane, nie ma co zbierać.