1Combine tomatoes, tomatillos, jalapenos and garlic in a saucepan. Bring to a boil, reduce heat, and simmer 15 minutes, or until tomatoes are soft. Remove from heat and allow to cool slightly.
2Peel, pit and slice avocados, set aside. Place tomato mixture, avocados, cilantro and salt in food processor. (You may need to do this in batches.) Process until smooth. Pour mixture into a large bowl; stir in sour cream. Cover with plastic wrap and refrigerate. Serve in small bowls with chips.