Add ground beef, taco seasoning and onion to a large heavy bottomed skillet over medium-high heat. Cook the meat and onions, breaking apart the meat as it cooks.
Drain off any excess grease. Add a can of diced tomatoes & green chilies and stir to combine.
Add cornstarch and stir until well combined. Slowly add beer and milk, while constantly stirring. Bring to a simmer and cook for 3 minutes.
Add cream cheese and cook, stirring often, until melted completely. Then add in the shredded cheddar cheese and stir until melted and well combined.
Serve immediately with tortilla chips, or keep warm in a crockpot on the warm setting for up to 8 hours.
