Empalagando comes from the verb empalagar, which describes the feeling of being overwhelmed by something that is excessively sweet, like a rich dessert. It's a fantastic word that doesn't have a perfect one-word translation in English.
In "Qué Más Pues?", María Becerra uses it metaphorically to shut down J Balvin. When she sings, "me estás empalagando y eso que no es golosina" (you're cloying me, and you're not even candy), she's cleverly saying his attention is so excessive and unwelcome that it's sickening.
This song is a whole conversation between two exes who run into each other, and it is spicy. It kicks off with J Balvin asking the classic question you ask someone you haven't seen in a while: "¿Qué más pues? ¿Cómo te ha ido?" [What's up then? How have you been?]. He immediately gets way too personal, asking if she's single or married. He blames fame for being distracted and losing track of her, but insists he wants another night to clear things up.
María Becerra is having none of it. She reminds him he's the one who lost track of her and that she's with someone new now. She has some amazing comeback lines, calling him out for being full of himself: "Tú sigues siendo el mismo engreído" [You're still the same conceited guy]. She tells him he's not boyfriend material and that he had his chance but was too distracted. When he says he called her, she hits him with the ultimate shutdown: "Yo a ti te llamé en agosto, apareciste en enero" [I called you in August, you showed up in January]. It's the perfect back-and-forth between someone trying to get a second chance and someone who has completely moved on.