Preheat oven to 350 degrees. Spray a 9x13 with cooking spray and set aside.
In a medium saucepan, combine diced tomatoes, tomato sauce, green chilis, and buffalo sauce. Bring to a simmer. Put about 1/2 cup of the sauce mixture along the bottom of the pan to coat the bottom. Reserve 2/3 cup of the sauce for the top.
Add the cream cheese to the sauce mixture and stir until melted in the sauce. Add the chicken and mix well.
Place about 1/4 cup of the chicken mixture off center to each tortilla. Roll up and place in the prepared pan seam side down. Repeat with remaining tortillas.
Top with reserved 2/3 cup of sauce and the monterey jack cheese. Bake for 15-20 minutes until heated through and the cheese is bubbly.