Heat oven to 350°F. Coat a 13 x 9 x 2-inch baking dish with nonstick cooking spray.
Melt butter in a large nonstick skillet over medium-heat. Add onion and cook for 5 minutes, stirring occasionally. Add chicken and cook 5 more minutes. Stir in chiles, cream cheese and salt. Turn off heat and stir until smooth.
Place oil in a small skillet and heat over medium-high heat. Place a tortilla in the oil and cook for a few seconds until tortilla becomes limp. Remove to a paper towel lined tray and repeat with the remaining tortillas.
Spoon about 1/3 cup of the filling down the center of each tortilla. Roll and set seam side down in baking dish. Pour half-and-half evenly over the top and sprinkle with the grated cheese.
Bake uncovered at 350°F for 23 minutes or until top is golden. Allow to cool slightly before serving.