In a oven safe skillet and over medium-high heat add chorizo and stir until it’s crumbled, browned and cooked through. About 5 minutes.
In the meantime, set broiler to high.
Once chorizo is done, transfer to a paper towel lined plate to drain.
Drain any leftover fat from skillet.
In the same skillet, melt the butter over medium heat. Whiskin the flour and cook for 1 minute.
Whisk in the milk and cook until slightly thickened. Less than a minute.
Remove from the heat and stir in 2 1/2 cups Monterey Jack cheese.
Sprinkle chorizo over top.
Then rest of the cheese.
Put the pan under the broiler and broil until the cheese is golden brown on top. Watch carefully. Should be about 5 minutes.
Remove from the oven, sprinkle with chopped cilantro.
Serve with tortilla chips.