Chavalitas is the affectionate, diminutive form of chavala, a colloquial word for a 'young woman' or 'girl'. While common in Spain, it's used in some parts of Mexico and in this song to mean something like 'gals' or 'chicks'.
As the song's title, this word is your key to unlocking its meaning. The singer lists all the different chavalitas in his life, giving you a window into the slang and culture of Regional Mexican music.
CHAVALITAS by Fuerza Regida is pure, high-octane hedonism wrapped up in fancy designer clothes and fast living. Right out of the gate, frontman Jesús Ortiz Paz flexes his lavish lifestyle with a chamarrita cuero paz bien fancy (really fancy leather jacket) and lists out the different women he is partying with. He bounces between una chavala que me diga 'Papi' (a girl who calls me 'Daddy') and una gabacha que me diga 'Fuck me' (an American girl who tells me 'Fuck me'). In Mexican slang, gabacha specifically means a white American woman. The whole track is loud, boastful, and completely unfiltered about late nights fueled by chaos, luxury brands, and wild flings.
The song really leans into street slang to show off how little he cares about blowing through cash. When he shouts otra vez en la pinche loquera (once again in the crazy madness), he is talking about getting lost in wild benders with foreign models and endless spending. He drops money on Cartier jewelry and houses without batting an eye: otra vez que me gasté una feria en ti (another time that I spent a fortune on you). In this context, feria is Mexican slang for cash or coin. He shrugs off the massive bill with no pesa, por ti, mi reina (it's no trouble, for you, my queen), treating heavy expenses like pocket change while cycling through fast romances he admits he will soon forget.