Healthy Taco Dip

4 cups shredded lettuce
3 medium ripe avocados mashed and mixed with 2 tbsp lemon juice
1 1/2 cup Greek yogurt mixed with 1 package low-sodium taco seasoning mix
1 can black beans
3 medium diced tomatoes
2 cans sliced olives
8 oz 2% cheddar cheese.