Chacaleo is a slang term for rowdy, boisterous roughhousing, often linked to street culture and the high energy of a wild party. It's part of a playful string of invented-sounding slang words that give the song its distinct, chaotic feel.
In the song, it appears in the repeated line "Chacaleo, malandreo, bellakeo, ma", where it piles up alongside similar party slang to paint a picture of unrestrained fun, dancing and a little mischief all rolled into one moment.