Heat oven to 350. Spray a 9" x 13" casserole dish w/ cooking spray. In lg non-stick skillet, over med-high heat, brown ground turkey or beef. Id using beef, drain the fat from skillet.
Add onion, green bell pepper, taco seasoning and 1/2 cup water, simmer, stirring for 10 mins. In bowl, stir togethet sour cream, mayonnaise, 1/2 cup cheese and 1 can chiles.
In another bowl, stir together bisquick mix and 3/4 cup water. Press bisquick dough into casserole dish. Layer w/ ground turkey mix and diced tomatoes. Spread w/ sour cream mix. Sprinkle w/ remaining cheese. Bake 30 mins, or until bubbly.