Preheat oven to 400F.
On a rimmed baking sheet sprayed with cooking spray, lay the fish. Dilute the dijon with the milk and brush that mixture over the fish. Season with salt and pepper.
Put the panko crumbs in a small bowl. Drizzle a little olive oil (~1/2 t) over, and using your fingers, toss the oil and crumbs together. Sprinkle over the fish.
Bake the fish at 400F for 8-10 minutes or until it flakes easily with a fork.
While the fish is cooking, saute the Swiss chard. Heat a large, nonstick skillet with 1 T olive oil on high heat. Add the garlic and Swiss chard and saute 1 minute to cook the garlic and wilt the greens. Add the wine and cook another couple minutes, stirring regularly, until liquid is mostly gone (this will remove the bitterness from the chard). Season with a pinch of salt.
To serve, divide the chard between 4 serving plates. Top with a piece of cod. Serves 4.