Heat a skillet over medium-high heat. Add butter and corn. Sprinkle with salt and chili powder. Cook 4 to 5 minutes without stirring too often, until corn is lightly golden and roasted. Remove from heat and let cool completely.
In a small bowl, whisk together Greek yogurt, mayonnaise, lime juice, garlic, chili powder, and salt until smooth. Taste and adjust seasoning.
In a large bowl, combine cucumber, red onion, pickles, chicken, and cilantro. Add cooled corn.
Pour sauce over the salad and toss until fully coated.
Taste and adjust — more lime for brightness, more chili powder for heat, more pickles for tang.
Serve immediately or refrigerate for 20 to 30 minutes before serving for best flavor.