Thrown Together and Yummy!

I bought a big tray of chicken breasts since we've been eating them almost every day. Today I got them cut and bagged and in the freezer. Except for a few for lunch. I didn't know what to do with them...

2 tbsp olive oil, divided
8 oz mushrooms, sliced
1 green onion, sliced
2-3 chicken breasts, slightly flattened
2 tsp mustard
2 tsp tarragon
1/4 c water

Heat 1 tbsp olive oil in a large skillet on medium-high. Saute the mushrooms. When they're almost done, add the green onions. Saute until mushrooms are browned. Remove from skillet and turn stove to medium. Heat the other tbsp of olive oil. Cook chicken breasts about 5 minutes per side until cooked through. Remove from skillet. Return veggies to skillet and add mustard and tarragon. Stir. Add water and stir, loosening browned bits from bottom of pan. Serve over chicken.