Acicalá' is a colloquial and shortened form of "acicalada," which means 'spruced up' or 'dressed up'. It refers to the act of grooming oneself carefully to look good.
In the song, Lucky Brown sings, "Salgo bonito, me pego una acicalá'" (I go out looking good, I get myself spruced up). This word perfectly captures the swagger and confidence of the artist, highlighting his focus on appearance before going out. It's a less common, more regional term that adds flavor to the lyrics.
"Me Veo Rico" opens with the narrator admitting something feels off: he's given up his old habits and pulled away from his old friends, and he's decided he only answers to himself now.
The rest of the song is him living out that decision. He gets dressed up, heads to the club, and repeats the hook that gives the song its title: he looks rich, he's out to misbehave a little, and nothing about the night is going to be ordinary. A second verse pushes further into that same confidence, with him driving around in a convertible, meeting new people and openly trying to forget someone who hurt him ("otra gata me voy a chichar" - moving on with someone else).
It's a straightforward night-out anthem from the Chilean urban scene: less about the person he's forgetting and more about the swagger he's putting on to do it.