For easy clean-up, line your slow cooker with a cooking bag.
Break chopped chuck into small pieces and place in slow cooker. Add beans and salsa verde.
Cover and cook on low for 6 - 8 hours.
Stir in corn in the last few minutes of cooking.
Divide lettuce among salad bowls. Using a slotted spoon, top lettuce with meat mixture.
Add desired toppings.