In A Large Skillet, Cook Steak In 1 Tablespoon Oil Over Medium-High Heat Until No Longer Pink; Drain. Remove And Keep Warm. In The Same Skillet, Heat Remaining Oil; Saute Peppers For 2 Minutes. Stir In Zucchini, Onion And Garlic; Cook And Stir 2 Minutes Longer. Add Peas, Mushrooms And Water Chestnuts. Saute Until The Vegetables Are Tender, About 2 Minutes. Return Beef To The Skillet. Combine Cornstarch, Broth And Soy Sauce Until Smooth; Add To Skillet. Bring To A Boil; Cook And Stir For 2 Minutes Or Until Thickened. Serve Over Rice.