Cook ground chorizo in a skillet over medium-high heat until browned. Allow to cool and drain excess grease.
Preheat the oven to 350⁰F.
Grease muffin pan bottom and sides.
In a medium-sized bowl, combine mix, milk, oil and egg. Stir until all the ingredients are well combined.
Add cooked chorizo, shredded cheese, one diced jalapeño, and bell pepper to the batter. Stir until well combined.
Scoop batter into each muffin cup, about 3/4 full. Top with a piece of sliced jalapeños.
Bake 18-20 minutes. Use a toothpick to check the center of the muffin. Serve warm and store extras in the refrigerator in an airtight container.