Dressing:
In a medium bowl, combine sour cream, mayo, olive oil, lime juice, chili powder, paprika, salt, and black pepper. Refrigerate until ready to use.
Salad:
Preheat grill for high heat. Brush corn with oil. Grill corn, turning every 2-3 minutes, until slightly charred on all sides. Cool and cut corn kernels off cob.
In a large bowl, combine cooked fusilli, corn kernels, cilantro, green onions, avocado, jalapeno, and cotija cheese. Pour the dressing and toss to combine. Finish with a sprinkle of Tajin. Enjoy!