Chamaca is a colloquial term, primarily used in Mexico and Central America, to refer to a young girl or a lass. It's a more informal and endearing term than just "girl."
In the song, the lyric "Se le nota de lejitos a la chamaca" (You can tell from afar with the young girl) uses this word to describe a young woman who is perhaps a bit shy or reserved, but whose interest is still noticeable. It adds a touch of regional flavor and a slightly more intimate tone than a standard word for girl.
"Glocko" is a Puerto Rican-style trap and reggaeton posse cut built on tough, boastful street talk. The title plays on "Glock" (the pistol) and "espantar" (to scare someone off): the hook, "voy a espantarlo' con la Glocko," turns the gun into a symbol of swagger and dominance rather than a literal threat.
Around that hook, the verses move between two familiar trap themes: flirty, explicit party bragging (dancing, clubbing, showing off) and displays of wealth and toughness (cars, weapons, expensive jewelry, bottles). Each guest gets his own moment to introduce himself, with Ithan Ny, Izahn and Lucky Brown all name-dropped near the end, so the "Glocko" hook becomes a shared catchphrase for the whole crew's confidence.
Heads up: the lyrics are sexually explicit and reference guns, which is why this lesson carries an explicit content rating.