To substitute canned or frozen corn, use approx 3 cups.
Cajun seasoning can be substituted with creole seasoning, Old Bay seasoning, 2 tbsp adobo sauce or this spice mixture: 2 tsp paprika or smoked paprika, 1/2-1 tsp cayenne pepper (depending on how spicy you want it) and 1/2 tsp each dried oregano and thyme.
Green chilies can be substituted with finely chopped 1 jalapeno or 1 small poblano pepper with the seeds removed.
