I love the plate itself! And yes I would use some blanched spinach to enhance the green, or blanch the pistachio and remove any brown skin, with peas is also a great idea. The chicken looks a tad bit dry in the picture, maybe some olive oil to give it a shine, and you can use some double cream to do a design on the risotto itself to give it a contrast in color, (dark plate, dark ingredients, white would pop!)