Stir the mayonnaise, yogurt, and taco seasoning together until smooth and refrigerate. (You can do this early if you want.)
Salad
Make *Jiffy cornbread according to package directions. Cool and cut into cubes.
Rinse and drain black beans. Drain corn.
Rinse, drain, and chop the lettuce and green onions.
Dice the tomato, you can drain them on a paper towel if you want to remove some of the juice.
Cut the avocado into chunks and squeeze lime juice over it. This prevents it from oxidizing (turning brown)
Combine the lettuce, black beans, corn, green onions, tomatoes, and cheese in a large bowl. Add the salad dressing, cornbread, and avocado (and chicken if you're adding it) and gently stir together being careful to not break apart the cornbread and avocado too much.
Top with crispy jalapenos or spoon into individual bowls and top with crispy jalapenos. Serve.
If you want to make this ahead of time and refrigerate. Leave the avocado and jalapenos out and add them just before serving.
Notes
crispy jalapenosfried onions*You can make your favorite cornbread recipe if you prefer. Ideally, one 8 or 9-inch skillet of cornbread is a good amount.