Preheat the oven to 350. Heat 2 tablespoons olive oil in a medium nonstick ovenproof skillet over medium heat. Add the onion, season with salt and pepper, and cook, stirring, until soft, about 8 minutes. Transfer to a bowl and wipe out the skillet.
Meanwhile, beat the eggs and 1 cup water in a large bowl. Season with salt and pepper. Lightly crush the potato chips into the egg mixture and let stand, stirring occasionally, until the chips are soft, about 10 minutes. Stir in the onion.
Heat the remaining 1 tablespoon olive oil in the skillet over medium heat, swirling to coat. Add the egg mixture and cook until it begins to set, about 5 minutes. Transfer the skillet to the oven and bake until the eggs are firm and the top is golden and slightly crisp, 30 to 35 minutes. Remove from the oven and let stand 5 minutes, then slide onto a plate. Cut into wedges and serve warm or at room temperature.