In a large skillet over medium heat, cook the ground beef until browned, breaking it apart as it cooks. Drain excess grease.
Add the chopped onion and garlic to the skillet. Cook for 2-3 minutes until softened and fragrant.
Stir in the diced tomatoes with green chilies, chili powder, cumin, salt, and black pepper. Let it simmer for 2-3 minutes.
Reduce heat to low and add the cubed Velveeta cheese, stirring frequently until melted and smooth.
Mix in sour cream to give the dip a creamy texture. If the dip is too thick, add a splash of milk to loosen it up.
Stir in shredded cheddar cheese for even more cheesiness.
Pour the dip into a serving bowl or a slow cooker set to warm. Serve with tortilla chips, crackers, or veggies.