Candela literally means "candle" or "fire". However, in many Latin American contexts, especially in music, it's used colloquially to mean "passion," "intensity," or even "trouble."
In this song, the lyric "Somos tremenda candela" (We are tremendous fire/passion) implies that the couple shares an incredibly intense, passionate, and vibrant connection. It's a more evocative and less common way to express strong chemistry than simply saying they have
Have you ever been so completely smitten with someone that you wouldn't change a single thing about them? That's exactly what Matisse and ChocQuibTown are singing about in "Nada"! This song is a super sweet declaration of love, where the singers are head-over-heels for their special someone, even down to their bad moods. They sing, "No te cambiaría nada, nada, nada / Tal como tú eres ya me encantas / Hasta tu mal humor a mí me enamoró" [I wouldn't change anything about you, nothing, nothing, nothing / Just as you are, I already love you / Even your bad mood made me fall in love].
It's all about that feeling when you're so obsessed you can't sleep, constantly dreaming of them, and thinking about them all day. They even say, "No he visto nada igual / Tú eres una en un millón" [I haven't seen anything like it / You are one in a million]. The song is full of playful promises, like giving them whatever they ask for and wanting to spend a whole Sunday in bed watching Netflix. It's truly a celebration of finding that perfect person who makes you feel completely loco (crazy) in the best way possible!