In a large skillet, saute onion, green pepper and jalapeno in oil until onion in tender. Stir in chicken. Remove from the heat; set aside.
For sauce, melt butter in a saucepan. Stir in flour until smooth. Add broth, cumin, garlic powder, salt and pepper. Bring to a boil; cook and stir for 2 minutes or until thickened and bubbly. Remove from the heat; stir in sour cream. Add 1 cup on the sauce to chicken mixture. Spoon 1/2 cup chicken mixture on each tortilla; roll up and place seam side down in a greased 13-in. x 9-in. baking dish. Pour remaining sauce over enchiladas.
Bake, uncovered, at 350° for 15 minutes or until sauce is bubble. Sprinkle with cheese. Bake 5-10 minutes longer.
Wear disposable gloves when cutting hot peppers; the oils can burn skin. Avoid touching your face.