Chicken with penne pasta in tomato sauce

3 Tbsp oil (divided)
1/2 onion, chopped
1 clove garlic, chopped
2-1/2 oz. jar mushrooms
1/2 large green bell pepper, chopped
1/2 large red bell pepper, chopped
1-1/2 lbs. boneless chicken breasts, cut into cubes
1 tsp. Italian seasoning (divided)
6 oz. can tomato paste
14 oz. can tomatoes, blended
1 lb. penne pasta

Saute onions & garlic in 2 Tbsp. of oil until onion is tender. Add mushrooms and bell peppers. Cook until peppers are tender. Remove vegetables from pan. Add chicken and 1 Tbsp. oil to pan. Sprinkle with 1/2 tsp. Italian seasoning. Cook until chicken is lightly browned, about 20 minutes. In a separate sauce pan, combine tomatoes, tomato paste and 1/2 tsp. Italian seasoning. Simmer while chicken cooks, at least 20 minutes. Cook pasta according to package directions. Drain noodles. Combine with tomato sauce. Top with vegetables and chicken.