chicken and wild rice casserole

Ingredients

• 2 cans cut green beans - rinsed and drained, (14.5 oz each)
• 2 cans chicken breast - drained and cut up (12.5 oz each) or 3 cups diced cooked chicken from freezer
• 1 - small onion - finely diced from freezer or fresh
• 1 jar diced pimiento (4 oz)
• 1 can cream of celery soup (10.5 oz)
• 1 can sliced mushrooms - drained (4 oz)
• 1 cup mayo
• 1 box Uncle Ben's long-grain & wild rice (original) (6 oz), cooked according to package
• 3 cups cheddar cheese - grated from freezer, divided
• - salt & pepper to taste