Mix the Southwest seasoning with the olive oil in a bowl add the chicken and rub the marinade into the chicken by hand. Allow to marinade for 4 hrs to overnight ( cover the bowl) turning once or twice.
Heat oven to 350
Place a skillet ( oven proof) on top of the stove and on a medium to high heat add the chicken and cook for 3 minutes. Flip chicken and repeat.
Stick skillet in oven and bake for 15 minutes.
Assemble salad while chicken is cooling. Cut chicken into 1/4 in slices and add to salad.