Nemam ništa za prijaviti means “I have nothing to declare” – the sentence you are most likely to need at the border.
The customs officer peers critically into your car and, through the cigarette fog, spots your mum, who can never keep quiet: fog, mum and “never” give you nemam. She is holding a cup with cream on it – ništa – and reaches into her jacket for a pinch of sugar. Then she waves the cup and asks the officer whether he would like a sip of her beastly good tea. Pinch, jacket and the beastly tea give you za prijaviti, and the jacket is extra large in the image – that is where the stress sits.
The next phrase is the “yes” version and ends in exactly the same way. So you get two sentences that share their second half.