Payouts roll out when a block is found.
The payment is made to the workers that helped finding the block in the percentage of the shares they contributed. Also, you get paid some percentage of the next blocks reducing untill the work you made is not relevant anymore. the payment system is PPLNS, this payment tends to favor pool fidelity, so you wouldnt get to much payments if you are always jumping pools.
The payment is made to your username, so your username should be you Nibble address