1. Cut each chicken breast into 4 strips, lengthwise, and place in a large bowl. In a separate bowl, whisk together 1 1/2 cups buttermilk and hot sauce until blended. Pour over chicken; mix until chicken is coated. Cover and refrigerate for 1 hour.
2. Make dip: In a medium bowl, combine sour cream, 1/2 cup buttermilk, blue cheese, vinegar and Worcestershire sauce. Whisk to mix well. Season to taste with salt and pepper. Cover and refrigerate.
3. Preheat oven to 350ºF. Mist 2 large baking sheets with cooking spray. In a food processor, pulse crackers until crushed. Add seasoning mix and pulse to combine.
4. Spread cracker mixture on a large platter. Remove chicken from marinade and carefully dredge each strip in cracker mixture.
5. In a large skillet, warm 2 Tbsp. oil over medium-high heat until shimmering. Add half of chicken and cook, turning, until brown and crisp on all sides, 2 to 3 minutes. Place on baking sheet. Repeat with remaining oil and chicken.
6. Place baking sheets in oven and bake until chicken is cooked through, 8 to 10 minutes. Serve chicken hot with celery and blue cheese dip.