Even terms like "impossible" or "never" have to be intended in relation to humanity. Not to some abstract concept that our minds cannot even comprehend.
That you randomly do always the best move in a chess game purely by chance is impossible. It will never happen.
In fact considering 20 possible moves in every position, and assuming with perfect play the GM would be defeated in only 40 moves, the chances of this happening are 1 out of 1.099511627776e+52
You know what that number means?
It means that it's impossible.
Chimp has no chance. Chimp will die of old age before having even started.
You can play chess as a random game, just make random moves. If there is a best move in a position, your chance of making it is simply 1/(number of possible moves).
The chimp has a chance.