In a 12-inch cast-iron skillet or non-stick skillet, heat oil over medium-high heat and saute the chiles and onion with the chorizo, until vegetables are soft and chorizo is cooked, about 5 minutes.
Reduce the heat to low and add Velveeta cubes and stir until Velveeta has melted and is smooth and creamy. Slowly add milk if the queso is too thick. Add as much or as little as you like to achieve your perfect consistency.
Add canned tomatoes and cilantro and stir to combine. Serve with tortillas chips.
Party Tip: Queso con Carne is best served warm. To do this, simply transfer the queso to a slow cooker to keep warm. This also works great as a way to transport it to your next family gathering.