Chambeando is a colloquial and very common term in many Latin American countries, especially Mexico, meaning "working hard" or "grinding". It comes from the word "chamba," which means "work" or "job."
In "Bendecido," Edgardo Nuñez uses chambeando macizo (working really hard) to emphasize his dedication and effort in achieving his success. It's an engaging word because it reflects a down-to-earth, hustler mentality that resonates with many listeners, making it memorable and relevant to the song's theme of overcoming adversity through hard work.
The whole song hangs on one memory: "Me humillaron solo por no tener" (they humiliated me just for not having). Edgardo Nuñez does not let it go, and he does not pretend it stopped stinging. He answers it with an inventory instead. Total black and LV, "Rolex en mano, si no, un buen Cartier" (a Rolex on the wrist, or else a good Cartier), an AMG he gets seen in. The flex is aimed at particular people who were there, which is what gives it teeth: "El que ha tenido no lo va a entender" (whoever has always had it is never going to understand).
What keeps it from being only that is the chorus. "Pero aquí andamos chambeando macizo" (but here we are, grinding hard) lands right after the jewellery, followed by a warning for everyone listening: "Pónganse pilas, no pierdan el piso" (get sharp, don't lose your footing). He sends the credit upward, "mi Dios me bendijo" (my God blessed me), and the line he keeps circling back to is not the Rolex at all. It is the before: "Si supieran que antes no traía ni un cinco" (if they only knew that before I didn't have a nickel).