Chicken and Spinach Pasta Bake

4 chicken breasts
1 (13 oz.) box short pasta, penne or rigatoni
1 8 oz. container chive and onion cream cheese
1 box frozen spinach OR about 2 c. fresh spinach
1 can diced tomatoes
salt and pepper to taste
2 c. shredded mozzerella cheese

Thaw chicken breasts. Dice chicken into small pieces then cook in skillet with olive oil and salt and pepper. Cook pasta according to directions. Drain, then add cream cheese and fresh spinach (if using) into hot pasta. Stir until spinach wilts and cheese melts. Add tomatoes and cooked diced chicken pieces into pasta mixture. Add salt and pepper. Pour into greased baking dish then top with mozzerella cheese. Bake for about 15-20 minutes at 400 degrees until hot and bubbly.