Cook the chorizo until it is done, drain. Combine the cooked chorizo in a mixing bowl with the ground beef, chili powder and salt. Mix together and form into 4 patties.
In a large skillet, heat the olive oil over medium-high heat. Add in the sliced poblanos and onion and saute until tender, 7-10 minutes.
On a grill set to medium-high heat, grill the burgers until desired doneness is achieved. About 2 minutes per side for medium rare. When you flip the burgers, top each with a slice of monterey jack, a heaping pile of the onion/poblano mixture, and then another piece of monterey jack.
Toast the buns and serve hot off the grill topped with guacamole.