Cut breasts into cubes and put in a bowl. Pour salad dressing over chicken and let marinate for about 30 minutes.
In a large skillet, heat olive oil to smoking hot. Dump chicken and salad dressing into skillet. Brown chicken pieces.
Add onion and garlic. Stir until onions are translucent.
Add can chicken broth to chicken. Add one can first. Decide if you have enough liquid to handle the spinach, if not add second can or part of the can until you feel there is enough liquid. I say this because sometimes the chicken will release lots of juice and sometimes it won't. Bring to boil.
Add baby spinach leaves to chicken and broth.
Cook linguine according to your liking of tenderness.
Just before you are ready to add pasta to the mix, add Romano cheese, stir well. Then toss with pasta