14ouncesdiced tomatoes with green peppers and onions1 can
4cupsshredded Mexican cheese blenddivided
Press Sauté; melt 1 tablespoon butter in Instant Pot®. Add onion; cook and stir 3 minutes or until softened. Stir in water, macaroni, tomatoes and salt; mix well.
Secure lid and move pressure release valve to Sealing position. Press Manual or Pressure Cook; cook at high pressure 4 minutes.
When cooking is complete, press Cancel and use quick release.
Press Sauté; add 3 1/2 cups cheese, milk and remaining 3 tablespoons butter to pot. Stir until smooth and well blended. Stir in salsa. Press Cancel. Sprinkle remaining 1 cup cheese over pasta; let stand until melted.