In a large skillet over medium-high heat, brown the ground beef, breaking it up with a spoon, until fully cooked, about 8-10 minutes. Drain excess fat.
Stir the taco seasoning into the cooked beef and add 1/4 cup water, simmering for 2-3 minutes until the mixture thickens.
Transfer the seasoned beef to the slow cooker and add the cream cheese cubes, black beans, pinto beans, corn, diced tomatoes with green chiles, cheddar cheese, Monterey Jack cheese, and salsa. Stir to combine.
Cover and cook on LOW for 2 hours, stirring every 30 minutes, until the cheese is melted and the dip is smooth and creamy.
Switch to the warm setting for serving and stir occasionally to maintain a smooth consistency.
Serve with tortilla chips and offer bowls of sour cream, green onions, and jalapeƱos on the side for topping.