In a medium bowl, whisk together the Greek yogurt, mayonnaise, mango chutney, curry powder, turmeric, and lemon juice until smooth and evenly combined.

Combine filling

Add the shredded cooked chicken, diced celery, raisins, and sliced green onion to the bowl with the dressing. Fold gently until the solids are coated evenly.

Season & finish

Taste and season with salt and black pepper. Stir in the toasted sliced almonds, reserving about 1 tablespoon for garnish. If the mixture seems dry, add an additional 1 tablespoon of yogurt or chutney to reach desired creaminess. Cover and chill for at least 15 minutes to allow flavors to meld (up to 2 hours).

Assembly & Bread

Toast bread

Preheat a skillet or griddle over medium heat (or preheat oven to 350°F / 175°C). Lightly butter one side of each slice of whole wheat bread. Toast buttered side down in the skillet until golden brown and crisp, about 2–3 minutes per side, or place buttered-side up on a baking sheet and bake 6–8 minutes until golden.

Assemble sandwiches

Place a lettuce leaf on four of the toasted bread slices (butter side down). Spoon about 3/4 cup of the chilled coronation chicken mixture onto each lettuce-lined slice, spreading evenly but leaving a small border. Sprinkle reserved toasted almonds and an extra 1/2 teaspoon mango chutney over the filling if desired. Top with the remaining toasted bread slices, buttered side up, and press gently.

Slice

Cut each sandwich in half diagonally or straight down the middle, wiping the knife between cuts for a clean edge.

Sides & Garnish

Divide chips between plates alongside sandwiches. Sprinkle extra toasted almonds over the sandwiches or plate, and serve extra mango chutney on the side for dipping.