Select saute setting on a 6-qt. electric pressure cooker and adjust for medium heat. Add butter. When melted, add mushrooms, onion, sweet pepper, 1/2 teaspoon salt and 1/2 teaspoon pepper; cook and stir until tender, 6-8 minutes. Add garlic; cook 1 minute longer. Stir in flour until blended. Gradually whisk in broth. Bring to a boil, stirring constantly; cook and stir until thickened, 1-2 minutes. , Stir in cream and noodles. Lock lid; close pressure-release valve. Adjust to pressure-cook on high for 3 minutes. Allow pressure to naturally release for 3 minutes, then quick-release any remaining pressure. , Meanwhile, in a small bowl, combine tuna, lemon juice and remaining salt and pepper. Select saute setting and adjust for low heat. Stir cheese, tuna mixture and peas into noodle mixture. Cook until heated through. Just before serving, sprinkle with potato chips.