Easy Chicken and Broccoli Lo Mein

I made this for dinner tonight and everyone seemed to like it. It was so fast and easy AND incorporated some veggies (I'll try anything to get my kids to eat healthy).
8 ounces long pasta, such as linguine
2/3 pound skinless, boneless chicken breasts
1 cup fresh button mushrooms (I didn't have any, but it would be a great addition)
1 T. peanut oil or vegetable oil
1 large onion
1 bag (16 oz.) frozen broccoli (I just used a few crowns of fresh broccoli that I steamed)
3 cloves fresh garlic
2 tsp. finely minced fresh ginger
3 T. soy sauce
1 T. rice vinegar
1 T. ketchup
1 tsp. dark sesame oil

Boil noodles until tender. Meanwhile cut chicken into bite size pieces. Heat oil in deep skillet and sauce chopped onion. Next add the chicken. Let that cook for a few minutes and then add the mushrooms, broccoli, garlic, and ginger. Cook, stirring frequently, until the mushrooms release their liquid and the chicken is no longer pink.

Add the soy sauce, vinegar, ketchup (I thought this was a really odd ingredient for this recipe-but it worked), and sesame oil to the skillet and mix well. Remove the skillet from heat and add the drained, cooked pasta. Mix all together are serve immediately.