Coarsely mash avocados and stir in green onions and lime juice. Season. Spread over the base of a 4 cup capacity serving dish.
Gently stir the sour cream and seasoning together and spread evenly over the avocado layer. Cover and refrigerate for 1 hour, or until firm.
For the salsa; combine the tomatoes, lime juice and olive oil. Season. Cover and set aside until ready to serve. Cut the corn from the cob. Place onto a microwave-safe plate and top with a piece of damp paper towel. Microwave on High/100% for 45-60 seconds or until just tender and bright yellow. Allow to cool.
Just before serving, sprinkle the cheese over the sour cream layer and top with corn. Add the coriander and jalapenos to the tomato salsa and spoon over the dip. Serve with corn chips.