Chambear is a very common slang verb in Mexico and other parts of Latin America that means "to work," often with the connotation of hustling or grinding.
It comes from the noun chamba (a job or gig). In the song, Junior H explains his backstory, singing that "el viejo lobo... se puso a chambear" (the old wolf... started to work/hustle) to make things happen. It's a fantastic, everyday word that will make your Spanish sound much more natural and is a perfect example of the real-world vocabulary you can learn from music.
Junior H comes out swinging in this track as a hardened veteran of the streets, calling himself a "viejo lobo en la manada" (old wolf in the pack) who laughs off younger rivals ("cachorros" / pups) because they don't have the hands to take him down. Comparing his hot streak to basketball legend Michael Jordan with "ando como Jordan" (I'm walking like Jordan), he dives headfirst into wild excess. He's blunt and funny about it too, cracking that he stays up late "chingando modelos y estoy bien culero" (hooking up with models even though I'm ugly as hell). The party keeps rolling with thick gold chains, blunts ("este gallo"), and endless cash ("feria"), with the singer daring the night to end only when he finally runs out of money to burn.
Beneath the flexing and luxury, Junior H drops the party mask to show you why he chased that money in the first place. He flunked school ("el malnacido que falló en la escuela") and had to grind hard ("se puso a chambear") just to escape his block and pay for his sister's education. Even with all the wealth, he admits he is buying heavy chains just "llenando el hueco que siento por dentro" (filling the emptiness I feel inside). It turns a rowdy trap-corrido anthem into a blunt confession about hiding loneliness behind thick stacks and reckless fun.