Cook ground beef in a large skillet over medium heat until it starts to brown.
Add chopped onion to the pan breaking up beef into small crumbles with a wooden spoon as it cooks.
Drain off any excess fat.
Add ½ a can of enchilada sauce and 1 tablespoon taco seasoning to the browned beef.
Stir and heat until sauce reduces, about 3-4 minutes, stirring occasionally. Set aside.
In a mixing bowl stir together softened cream cheese with the can of refried beans until well combined. Set aside.
Pour ½ a can of enchilada sauce in the bottom of the slow cooker.
Top with a layer of corn tortillas. Cut them to size if needed.
Spread ½ the cream cheese/bean mixture over the tortillas.
Top with ½ the taco meat.
Top with a cup of shredded cheddar cheese.
Pour ½ a can of enchilada sauce over the cheese.
Repeat layers; tortillas, ½ the beans, ½ the meat, 1 cup shredded cheese, and the remaining ½ can of enchilada sauce.
Top with a final layer of tortillas, 1 cup of shredded cheddar cheese and sliced black olives.
Cover and cook for 2-3 hours on low or until hot and ingredients are heated through.
Top each serving with sliced avocado, a dollop of sour cream and a sprinkle of green onions.