In a skillet over medium heat, cook the chorizo until browned and cooked through, about 5-7 minutes. Remove the chorizo from the skillet and set aside, leaving the drippings in the pan.
In the same skillet, add the olive oil, onion, and garlic. Sauté until the onion is translucent, about 3-4 minutes.
Reduce the heat to low and add the Monterey Jack and cheddar cheeses to the skillet. Stir until the cheese is melted and creamy.
Add the cooked chorizo back into the skillet along with the diced tomatoes, cilantro, cumin, chili powder, salt, and pepper. Mix well to combine all ingredients.
Cook for an additional 2-3 minutes until everything is heated through.
Serve immediately with tortilla chips or warm tortillas for dipping.