Grease a casserole dish that will fit 4 boneless skinless chicken breasts, a 9 x 9-inch or comparable size.
Preheat oven to 375 degrees.
If you'd like to saute your chicken first, mix the flour and salt in a large Ziploc bag, then seal Add the chicken and shake until coated.
Heat the olive oil in a saute pan. When hot, add the chicken and cook for 2-3 minutes per side, just until lightly browned.
Remove and place in prepared dish. Sprinkle one side of the chicken with taco seasoning, flip, and repeat on the other side. Top with salsa.
Bake for 25-30 minutes or until chicken is cooked through. Sprinkle with cheese and return to the oven for 5 minutes or until cheese is melted.