Chavalos is a colloquial term in some Spanish-speaking regions, particularly Mexico, for 'kids' or 'young guys'. It's a more informal and regional word than the standard 'niños' or 'jóvenes'.
In the context of the song, the artist uses it to address a younger audience or those who might be new to the lifestyle he describes, saying, "Pa' que sepan bien chavalos" (So that you young guys know well). It adds a touch of authenticity and street credibility to the lyrics.
In "El Güero," Peso Pluma tells a story of survival, success, and caution. The narrator, who goes by the nickname "El Güero" and has the initials "FR," reflects on a life-changing event. He was shot thirteen times just two days before his birthday, but miraculously survived. This violent attack taught him a valuable lesson: "Ya no se puede confiar en nadie" (You can't trust anyone anymore).
As a result, he now lives a life of constant vigilance, always carrying a .40 caliber pistol for protection. Despite his youth, he's successful and enjoys the finer things, like expensive tequila and a nice watch. He's learned from life's harsh lessons and warns others that he is tough as a rock. The song paints a picture of a man who is calm and reserved on the surface but is always ready to defend himself and his success.