easy chicken breast recipe

1 pound fresh crab meat or imitation crab meat, shredded - 1/2 cup mayonnaise - 1 tablespoon Dijon mustard - 2 tablespoons lemon juice - 1/2 teaspoon Old Bay seasoning (optional) - 1/4 teaspoon garlic powder - 1/4 teaspoon onion powder - Salt and black pepper to taste - 2 celery stalks, finely chopped - 1 small red bell pepper, finely chopped - 2 green onions, chopped - 2 tablespoons fresh parsley, chopped - Mixed greens or lettuce leaves (for serving)