Preheat the oven to 350℉.
In a large skillet, cook the bacon until crispy. Transfer it to a paper towel-lined plate to drain, leaving about 2 tablespoons of the bacon grease in the skillet.
Add the drained corn and the white portions of the green onions to the skillet. Cook until the corn begins to brown, stirring occasionally. This step is optional, but it adds extra sweetness and smoky bacon flavor. Remove from the heat and allow the mixture to cool slightly. Once the bacon has cooled, chop it into bite-sized pieces.
In a large mixing bowl, whisk together the sour cream and eggs until smooth. Slowly whisk in the melted butter.
Add the Jiffy cornbread mix and stir just until combined. Fold in the shredded cheddar cheese, chopped pickled jalapeños, roasted corn mixture, and chopped bacon.
Spread the batter evenly into the prepared baking dish. If desired, sprinkle a little extra shredded cheddar over the top and arrange a few whole pickled jalapeño slices for a decorative finish.
Bake for 45–60 minutes, or until the top is golden brown and a toothpick inserted into the center comes out clean. Baking times may vary slightly depending on your oven.
Let the casserole cool for about 15 minutes, then garnish with the reserved green onion tops before slicing and serving.