In a large mixing bowl, combine sour cream and mayonnaise until smooth.
Stir in diced green chilies, sliced black olives, shredded cheddar cheese, shredded Monterey Jack cheese, taco seasoning mix, and salsa until well combined.
Cover the bowl and refrigerate for at least 1 hour to allow the flavors to meld together.
Garnish with extra cheese or cilantro and serve chilled with tortilla chips.
Notes
If you don't have salsa, you can replace it with the ingredients below: