Chicken Tostadas

Many years ago when my girls were in elementary school there was a school fair. A lady had a tostada  booth that we thought was amazing.  Of course, I had to work at recreating it. I love to do that.  It has been a long time, so I really don't know how close my creation is to hers, but we still like it.

2 chicken breasts ( I would prefer to use chicken on the bone and cook it down, but I don't have that on hand)
large can of diced tomatoes
1 cup chicken broth
salsa (use to add more moisture if needed while cooking,)
large onion
red pepper flakes (to taste)
Tostada shells

Cook whole chicken breasts in the rest of the ingredients on a medium/low heat.

This usually takes about 20 minutes or so.

Pull chicken out and shred.

Put back into tomatoes and let simmer for about 5 to 10 more minutes.
Warm shells in oven.
Put chicken mixture on top of shell.  Top with cheese and sour cream!  Ole!