I start with frozen chicken tenders. I like to use tenders because they cook really fast (and I get a giant bag from Costco).
1. Heat your oven to 400, line a baking sheet with aluminum foil, and put the frozen tenders on the foil.
2. Bake for about 15 minutes, or until the chicken is cooked all the way through (the meat doesn't have to be totally white to be cooked through--use an instant read thermometer if you're not sure if it's done).
3. When the tenders are cool enough to handle, shred or dice the chicken for your recipe. 3 tenders make about 1 cup shredded chicken. I often make more than I need and then freeze the extra in 1 cup measurements to use later.