Prepare the dressing. Add the mayonnaise, lime juice, chili powder, salt, and ground black pepper to a small mixing bowl. Whisk until well combined.
Place the coleslaw, green onions, jalapenos, cheese, and cilantro in a large mixing bowl. (A large bowl with a lid would be great because you'll need to cover and refrigerate it.)
If you're using fresh corn, you'll need to cook it through, then cool it. For frozen corn, prepare it as directed on the package, then allow it to cool. For canned corn, you can drain it and add it directly to the bowl with the other produce ingredients. Regardless of what kind you use, drain it very well. Otherwise, the liquid will dilute your dressing. Add the corn to the bowl with the coleslaw.
Pour the dressing over the vegetables and toss until thoroughly mixed.
Cover and refrigerate for at least one hour up to 10 hours before serving.
Store any leftovers covered in the refrigerator for up to 24 hours.