Saute ground beef with chopped onions until cooked through. If you desire, drain excess grease from the pan.
Set slow cooker on high heat and add tomatoes and tomato sauce. Top with black beans, kidney beans, green chiles, and corn.
Next, add in all of the seasonings: cumin, chili powder and taco seasoning. Stir everything in the slow cooker until combined.
Add beef on top (do not mix in), Velveeta, and then the milk. Place the lid on the slow cooker and cook on high 2 hours.
Remove lid and stir to combine. Add in shredded cheddar cheese and cilantro, stir to combine. Replace lid back on and cook for another hour.
Remove lid, stir to combine and serve. Keep slow cooker on warm, while you are serving.
If it sits for too long, you may need to add an extra 1/4 cup milk to thin the cheese dip.
Great as a dip with taco chips, tortillas, crackers or even make as a topping to a burrito or taco salad!