Heat oven to 400 degrees.  

Line a plate with paper towels.  In a cast iron skillet over medium heat, fry chorizo, onion and peppers until cooked. Once it’s cooked, place chorizo mixture on the paper towel and press out as much fat and liquid as possible.  Wipe the cast iron skillet clean.  Place chorizo back into the bottom of the skillet and cover with grated cheese.  

Place in oven and bake for 10-15 minutes, just until cheese is melted right to the middle.  It will start to get stringy if baked too long, so watch carefully.  Remove from oven and serve immediately with tortilla chips or soft taco shells.