Make the cream cheese layer: In a medium bowl, beat together the softened cream cheese, 1 cup sour cream, and taco seasoning until smooth and creamy (about 2 minutes with a hand mixer).
Spread the base: Spread the cream cheese mixture evenly in a 9x13 inch dish or large serving platter, making sure to reach all the edges.
Add the salsa: Pour the salsa over the cream cheese layer and spread gently with a spoon. Keep the layers distinct—don't mix them together.
Top with cheese: Sprinkle the shredded Mexican cheese blend evenly over the salsa layer.
Chill (optional): For best flavor, cover with plastic wrap and refrigerate for 30 minutes to 2 hours. This step is optional but recommended.
Add fresh toppings: Right before serving, layer on the lettuce, tomatoes, black olives, red onion, and jalapeños.
Finish and serve: Drizzle with the remaining sour cream and scatter fresh cilantro on top. Serve immediately with tortilla chips.