Preheat the oven to 450 degrees. Combine the grapes, walnuts and chives and set aside.
Combine the goat's cheese with the parsley and thyme and season well to taste with salt and pepper. Mix a tablespoon or more of mustard and the lemon juice in the melted butter and brush some of this mixture over each tortilla. Set them on a baking sheet and top with some chicken and goat's cheese. Bake for 5 minutes or until warmed throughout and cheese has melted somewhat. Remove from oven, fold in half and serve topped with the grape, walnut and chive mixture.