Preheat oven to 400°F. Line a baking sheet with parchment or a silicon baking mat.
Prepare the tartar sauce by combining ½ cup mayonnaise with the pickles, capers, lemon juice, mustard, a small pinch salt, and pepper in a small bowl. Cover and refrigerate until serving.
Coarsely crush the potato chips and place in a shallow bowl or plate.
Pat the fish dry, brush all over with the remaining mayonnaise, and coat with the crushed potato chips, firmly pressing the chips into the fish. Place on prepared baking sheet and bake for 12 – 15 minutes or until the fish flakes easily.