Mix the beans: In a small bowl, combine the canned refried beans with 3 tablespoons of water and stir until smooth and spreadable, about 1-2 minutes.
Spread evenly: Transfer the bean mixture to the bottom of a 9x13 inch baking dish or large platter, creating an even layer using a spatula.
Mix the topping: In a small bowl, combine 2 cups of sour cream with the entire 1 ounce packet of mild taco seasoning, stirring until fully blended and evenly seasoned, about 1-2 minutes.
Spread smoothly: Spread the seasoned sour cream evenly over the bean layer, making sure to cover all edges and create a smooth, even surface.
Layer the guacamole: Spread the 1.5 cups of premade mild guacamole evenly over the sour cream layer, working gently to avoid mixing the layers.
Add the salsa: Spoon the drained chunky mild salsa evenly over the guacamole, allowing some of the vibrant red color to show through.
Top with lettuce: Distribute the 2 cups of shredded lettuce across the salsa layer, covering it completely.
Cheese layer: Sprinkle the 2 cups of pre-shredded fiesta blend cheese evenly over the lettuce.
Garnish: Top with the well-drained sliced black olives, followed by the chopped roma tomatoes and thinly sliced green onions, creating an attractive, colorful presentation.