Cut chicken into cubes. In saucepan, melt butter & add flour. Stir & cook 1 min. Add 1 cup of milk & the broth, stir over medium heat until thickened, about 5 mins. Stir in oregano & season with salt & pepper. Set aside. Heat oil in large skillet & add chicken. Cook until browned on all sides. While chicken is cooking, make the dough for the dumplings: in a bowl, combine baking mix with remaining milk until sticky dough forms. When chicken is browned, add sauce & veggies to skillet and stir until combined. Spoon large tablespoons of dough on top of mix in skillet. Turn heat to low, cook uncovered for 10 minutes, then covered for 10 mins more. Place one or two biscuits on each plate, then spoon chicken & sauce over top. Yum!