In food processor combine chard, basil, garlic scapes, a pinch of kosher salt and water. Mix on medium speed while slowly adding olive oil. After all the oil is added mix on high until greens are a pesto consistency. You will have extra pesto that can be stored up to seven days in the refrigerator.
Lay fish fillets skin side down on a sheet of aluminum foil. Lightly salt and pepper fillets to taste.
Spread pesto mixture over fish, coating the fillets evenly.
Layer tomatoes and mozzarella cheese slices over fish fillets. Leave fish open for cooking.
Oven bake at 375 for 12 minutes. Check every 2 minutes after until flakey. Or grill on med-high heat for 10 minutes. Check every 2 minutes after until flakey.