Cook noodles in boiling salted water till tender; drain. Combine cooked noodles, drained tuna, mayonnaise, onion, celery, peas.
Blend soup and milk in a saucepan over low heat. Add cheese and salt and pepper to taste; stir until cheese is melted. Add to noodle mixture. Spray a casserole dish with Pam. Put mixture into casserole dish and sprinkle crushed potato chips on top.