Spray a 4- to 5-quart slow cooker with nonstick cooking spray.
Microwave the frozen corn uncovered on High for 2 minutes or until thawed. ( You can skip this step if you like. It'll cook for 8 hours in the crock pot.
Add corn, beef, and all remaining stew ingredients to the slow cooker; stir to combine.
Cover and cook on Low for 8–10 hours (or High for 4–5 hours) until the beef is fork-tender.
Divide stew evenly among six bowls. Top each with avocado slices, crushed tortilla chips, cilantro, and a spoonful of sour cream.