Preheat the oven to 350.

Combine the basil, pine nuts, Parmesan, garlic, oil, water, lemon juice, nutmeg, salt and pepper in a food processor and process until ingredients form a paste.

Place the flatbreads directly onto the middle rack of the oven and bake for about 3 ½ minutes until they stand firm when lifted. Spread the pesto evenly in a thin layer across the flatbreads, leaving a bit of space around the edges for a crust. Each flatbread will get about 1 ½ tablespoons of pesto. Sprinkle the cheese over the pesto and then the chicken over the cheese. Add the tomatoes over the top and return the flatbreads to the oven, directly on the rack (make sure no ingredients are hanging over the edge). Bake for another 4-5 minutes until the flatbread is browned and cheese is melted. Slice with a pizza cutter and serve.