In a medium bowl, combine sour cream, taco seasoning and mayonnaise and mix well. Chill in refrigerator while preparing rest of dip.
In a separate bowl, mash ripe avocados with lime juice and garlic salt. Set aside.
Open cans of bean dip and spread in an even layer on the bottom of a glass pie plate or similar style dish (or layer in a trifle dish, as pictured).
Next, carefully spread the guacamole in another even layer on top of the bean layer.
Spread the sour cream mixture for the top layer, ensuring to spread to the edges.
Top with cheese, tomatoes, scallions, and olives.
Cover, and chill for 1 hour before serving. Serve with tortilla chips.