Melt the butter in a large pan over medium-high heat.
Add the corn and cook, stirring occasionally, until the kernels are nicely browned, about 6–10 minutes; season lightly with salt while cooking (about 1/2 teaspoon, optional).
Transfer the browned corn to a large bowl and allow it to cool completely.
To the cooled corn, add the diced rotisserie chicken, diced red bell pepper, chopped cilantro, sliced green onions, diced jalapeño (if using), and diced avocado.
In a small bowl, whisk together the mayonnaise, chili powder, paprika, ground cumin, Sriracha, lime zest from 1/4 teaspoon, and 3 tablespoons lime juice; season with salt (about 1/4 teaspoon) and pepper (about 1/8 teaspoon), adjusting to taste.
Pour the dressing over the salad ingredients and gently stir until everything is evenly coated; taste and add more lime juice, salt, or pepper as desired, then serve immediately.