Here are the widely agreed “best” crispy chicken sandwiches you can get at fast-food/fast-casual restaurants in the U.S., with a short note on what makes each one stand out and a quick ordering tip.

1. Popeyes — Classic Chicken Sandwich

   • Why: Very crunchy, well-seasoned hand-breaded fillet on a buttery brioche with pickles; big, flavorful bite.
   • Tip: Try the spicy version or add extra pickles.

2. Chick‑fil‑A — Original / Spicy Chicken Sandwich

   • Why: Simple, famously juicy and well-seasoned breading; high-quality bun and pickles make it balanced.
   • Tip: Order the Spicy or Deluxe (with cheese/lettuce/tomato) if you want more complexity.

3. Shake Shack — Chick’n Shack

   • Why: Crispy, crisper-than-average coating with herbaceous mayo and a soft potato bun — good fast-casual upgrade.
   • Tip: Add cheese and ShackSauce for more richness.

4. KFC — Crispy Chicken Sandwich (Classic or Double)

   • Why: Double-breaded, crunchy coating and bold KFC seasoning; often larger-than-average fillet.
   • Tip: The Classic with pickles is the straightforward winner; try the mayo/spicy variants if available.

5. Wendy’s — Homestyle/Spicy Crispy Chicken Sandwich

   • Why: Thicker, more “chickeny” fillet with a crunchy coating and fresh toppings; reliable and widely available.
   • Tip: Ask for toasted bun and extra pickles or sauce.

6. Carl’s Jr. / Hardee’s — Big Chicken Hand-Breaded Sandwich

   • Why: Hearty, hand-breaded fillet, big portion and robust breading; good if you want a meaty, crunchy sandwich.
   • Tip: Try it with bacon or pepper jack for more texture and heat.

7. Burger King — Crispy Chicken Sandwich (or Ch’King when available)

   • Why: A sizable, crunchy fillet with a straightforward flavor profile that’s widely available.
   • Tip: Add a spicy sauce or cheese for more flavor punch.

8. Jack in the Box — Crispy Chicken Sandwich

   • Why: Solid, crispy breading and value-oriented price; good late-night option at many locations.
   • Tip: Try it with their spicy sauce or add extra lettuce/tomato.

Notes and ordering tips

• “Extra crispy” or asking for the sandwich to be made fresh improves crunch.
• Avoid heavy sauces until the sandwich is handed to keep the coating from getting soggy.
• Brioche or toasted potato buns help contrast the crunch with richness.
• Availability/variant names can vary by region and over time, so if you’re after a specific version (spicy, double, deluxe), check the menu at the location.

If you want, I can rank these for a specific region (e.g., your city/state) or give nearby fast-food locations that have consistently good versions.