Próximamente nada is a unique and poetic phrase that literally translates to "soon to be nothing" or "next to nothing". It's not a common idiom, making it particularly striking.
In the song, Luis Coronel uses this phrase to describe the fading love and presence of his partner. He sings, "Serás de mí, Próximamente nada," meaning she will soon be nothing to him, highlighting the painful realization that their relationship is ending. This phrase beautifully captures the bittersweet essence of a love that is slipping away.
"Próximamente Nada" is a breakup song that turns the title into a threat. Luis Coronel starts calm, almost fair about it: "A un corazón" / "No se le puede obligar a dar amor" ["A heart can't be forced to give love"], and he says he won't blame her for going. But the line he repeats like a warning label flips that fairness on its head: "Próximamente nada" ["Coming soon: nothing"]. He's telling her exactly what's about to disappear: "Ya se fue" / "El brillo en tu mirada" ["It's already gone, the spark in your eyes"].
The second half moves the same idea forward in time. He imagines catching her in love with someone else after he "por completo te entregué mi corazón" ["completely gave you my heart"], and all he wants back is an answer for what was missing. It's a small, specific complaint dressed up as a prediction, which is why the song lands more like a shrug than a scream.