In a medium mixing bowl, stir together the sour cream and taco seasoning until combined. Set aside.
To another mixing bowl, add the avocado, lemon juice, salt, and pepper. Mash everything together with a fork until mostly smooth. Set aside.
Open the can of beans and stir to loosen them up so they're easier to work with. Spread the beans in an even layer in the bottom of a 9-inch x 13-inch baking dish.
Spread the avocado mash over the beans so they're completely covered. Then spread the seasoned sour cream over the avocados, covering the previous layer.
Sprinkle the shredded cheese over the dip and then top with the tomatoes and olives. Sprinkle the green onions and/or cilantro over the top.
Cover with plastic wrap and store in the fridge until ready to serve, or serve immediately with a big bowl of tortilla chips for dipping.
Notes
If desired, you can substitute two 9-ounce cans of Fritos bean dip instead of refried beans (found in the chip aisle), and use store-bought guacamole instead of making the avocado mash. I recommend Wholly Guacamole brand, it's my favorite.