Preheat the broiler (overhead grill) to high).

Place the low carb tortillas on a baking sheet lined with a silicone mat or kitchen foil and cook them under the broiler until crispy but not burnt. Turn them over and cook the other side until they start to darken at the edges.

Add the chicken to the tortillas, and divide some shredded cheese over the top. Return to the broiler until the cheese has melted.

Transfer the tostadas to serving plates and load them up with salsa, shredded lettuce, diced avocado, sour cream, and sliced jalapeños (if using).

Finish with a grind of black pepper and serve immediately.